{"id":12982,"date":"2025-09-25T12:28:21","date_gmt":"2025-09-25T11:28:21","guid":{"rendered":"https:\/\/mcqsadda.com\/?p=12982"},"modified":"2026-01-19T04:19:32","modified_gmt":"2026-01-19T04:19:32","slug":"plant-hormones-top-100-mcqs-with-answer-and-explanation","status":"publish","type":"post","link":"https:\/\/mcqsadda.com\/index.php\/2025\/09\/25\/plant-hormones-top-100-mcqs-with-answer-and-explanation\/","title":{"rendered":"Plant hormones Top 100 MCQs With Answer and Explanation"},"content":{"rendered":"\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">1. The first discovered plant hormone is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Gibberellin<br>B) Cytokinin<br>C) Auxin<br>D) Abscisic acid<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Auxin was the first plant hormone discovered through phototropism experiments by Darwin, and later isolated by Frits Went.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">2. Who demonstrated that plant shoots bend towards light due to a chemical substance?<br><\/mark><\/strong>A) Charles Darwin<br>B) Kurosawa<br>C) Frits Went<br>D) Miller<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Darwin and his son Francis showed phototropism in canary grass coleoptiles, suggesting a mobile chemical (later identified as auxin).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">3. Who first isolated auxin from oat coleoptile tips?<br><\/mark><\/strong>A) Charles Darwin<br>B) Frits Went<br>C) Miller<br>D) Kurosawa<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  In 1928, Went collected diffusible substance from coleoptile tips, naming it \u201cauxin.\u201d\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">4. The naturally occurring auxin in plants is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Indole-3-acetic acid (IAA)<br>B) Indole-3-butyric acid (IBA)<br>C) Naphthalene acetic acid (NAA)<br>D) 2,4-D<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  IAA is the main natural auxin present in plants.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">5. Which auxin is widely used for rooting in stem cuttings?<br><\/mark><\/strong>A) IAA<br>B) IBA<br>C) 2,4-D<br>D) Kinetin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Indole-3-butyric acid is applied to induce root formation in cuttings.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">6. Which of the following is a synthetic auxin?<br><\/mark><\/strong>A) IAA<br>B) IBA<br>C) NAA<br>D) Zeatin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Naphthalene acetic acid (NAA) is a synthetic auxin.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">7. The auxin responsible for apical dominance is mainly produced in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Roots<br>B) Shoot tips<br>C) Leaves<br>D) Flowers<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxins produced in the apical bud suppress growth of lateral buds.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">8. The phenomenon of suppression of lateral buds by apical bud is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Phototropism<br>B) Apical dominance<br>C) Geotropism<br>D) Senescence<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxins from apical bud inhibit lateral buds, maintaining apical dominance.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">9. Removal of apical bud results in growth of lateral buds. This is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Pinching<br>B) Decapitation<br>C) Pruning<br>D) Defoliation<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Removing apical bud reduces auxin effect, allowing lateral buds to grow.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">10. Which synthetic auxin is used as a selective weedicide?<br><\/mark><\/strong>A) 2,4-D<br>B) NAA<br>C) IBA<br>D) Kinetin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>   2,4-dichlorophenoxyacetic acid kills broad-leaved dicots but not monocot crops.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">11. Which hormone promotes cell elongation in shoots?<br><\/mark><\/strong>A) Auxin<br>B) Cytokinin<br>C) ABA<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Auxins promote loosening of cell wall, aiding elongation.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">12. Which hormone promotes parthenocarpic fruit development?<br><\/mark><\/strong>A) Cytokinin<br>B) Gibberellin<br>C) Auxin<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Auxins induce fruit formation without fertilization.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">13. Which hormone delays leaf abscission?<br><\/mark><\/strong>A) ABA<br>B) Ethylene<br>C) Auxin<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Auxins prevent leaf and fruit drop by inhibiting abscission layer formation.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">14. In tissue culture, auxins are mainly used for<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Shoot differentiation<br>B) Root initiation<br>C) Senescence delay<br>D) Fruit ripening<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxins induce root formation from callus in tissue culture.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">15. Which auxin is used to prevent premature fruit drop in orchards?<br><\/mark><\/strong>A) IAA<br>B) IBA<br>C) NAA<br>D) Zeatin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Naphthalene acetic acid prevents abscission of developing fruits.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">16. Which plant response is controlled by lateral movement of auxin?<br><\/mark><\/strong>A) Thigmotropism<br>B) Phototropism<br>C) Chemotropism<br>D) Nastic movement<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxins accumulate on the shaded side, causing bending towards light.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">17. In geotropism, auxins move towards<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Upper side<br>B) Lower side<br>C) Equal distribution<br>D) Leaves<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxins accumulate on lower side of root\/shoot in response to gravity.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">18. In roots, higher auxin concentration causes<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Increased elongation<br>B) Inhibition of elongation<br>C) Parthenocarpy<br>D) Apical dominance<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxins promote elongation in shoots but inhibit elongation in roots.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">19. Synthetic auxin commonly used for fruit thinning in apple and grape cultivation is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) NAA<br>B) 2,4-D<br>C) IBA<br>D) Zeatin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  NAA prevents overcrowding of developing fruits.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">20. The discovery of auxins was based on experiments on<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Maize endosperm<br>B) Oat coleoptile<br>C) Rice seedlings<br>D) Wheat roots<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Went\u2019s classic experiment used oat coleoptile tips to demonstrate auxin.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">21. Which auxin is naturally occurring in maize and other cereals?<br><\/mark><\/strong>A) IBA<br>B) IAA<br>C) NAA<br>D) 2,4-D<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  IAA is a universal natural auxin in higher plants.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">22. Auxins promote vascular differentiation. This is important in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Root initiation<br>B) Secondary growth<br>C) Fruit ripening<br>D) Senescence<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxins help in formation of xylem and phloem tissues.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">23. Auxins act by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Increasing cell wall plasticity<br>B) Inhibiting respiration<br>C) Closing stomata<br>D) Inhibiting protein synthesis<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Auxins activate proton pumps, loosen cell walls, and promote elongation.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">24. The process of fruit development without fertilization under auxin treatment is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Apomixis<br>B) Parthenocarpy<br>C) Polyembryony<br>D) Pollination<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxins induce seedless fruit development.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">25. Excessive application of auxins can cause<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Early flowering<br>B) Leaf abscission<br>C) Root initiation<br>D) Increased seed germination<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Though auxins normally delay abscission, excess concentration reverses the effect, causing leaf and fruit drop.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">26. Gibberellins were first discovered in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Maize kernels<br>B) Oat coleoptiles<br>C) Rice seedlings<br>D) Tobacco pith culture<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Kurosawa discovered gibberellin while studying \u201cfoolish seedling disease\u201d in rice caused by Gibberella fujikuroi.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">27. Which scientist is credited with the discovery of gibberellins?<br><\/mark><\/strong>A) Frits Went<br>B) Kurosawa<br>C) Miller<br>D) Darwin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  In 1926, Kurosawa linked abnormal growth in rice to a fungal metabolite, later named gibberellin.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">28. The main physiological effect of gibberellins is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Root initiation<br>B) Cell division<br>C) Stem elongation<br>D) Fruit ripening<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Gibberellins break dormancy, induce bolting, and cause internode elongation.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">29. Bolting in rosette plants like cabbage is due to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxin<br>B) Cytokinin<br>C) Gibberellin<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  GA causes elongation of internodes leading to bolting before flowering.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">30. Which hormone induces enzyme synthesis (amylase) during seed germination?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Cytokinin<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  GA stimulates aleurone layer to produce hydrolytic enzymes that mobilize stored food.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">31. Gibberellins can substitute for which environmental requirement to break seed dormancy?<br><\/mark><\/strong>A) Light<br>B) Low temperature<br>C) Water<br>D) Oxygen<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  GA can replace cold stratification in seed germination.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">32. Which hormone is commercially used to increase sugarcane yield?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Cytokinin<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  GA promotes stem elongation and enhances sugar accumulation in sugarcane.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">33. The hormone responsible for \u201cfoolish seedling disease\u201d is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxin<br>B) Cytokinin<br>C) Gibberellin<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Excess GA from fungal infection caused abnormal tall growth in rice seedlings.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">34. Which gibberellin is most biologically active?<br><\/mark><\/strong>A) GA\u2081<br>B) GA\u2082<br>C) GA\u2083<br>D) GA\u2087<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  GA\u2083 is widely used commercially and physiologically most active.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">35. Gibberellins induce seedless fruit formation (parthenocarpy) in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Tomato<br>B) Banana<br>C) Grapes<br>D) Pineapple<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  GA sprays are used to induce seedlessness in grapes.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>36. Which of the following is a cytokinin?<br><\/strong><\/mark>A) Indole-3-acetic acid<br>B) Zeatin<br>C) Gibberellin A\u2083<br>D) Abscisic acid<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Zeatin is a natural cytokinin isolated from maize kernels.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>37. Cytokinins were first discovered by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/strong><\/mark>A) Frits Went<br>B) Kurosawa<br>C) Miller<br>D) Darwin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  In 1955, Miller discovered kinetin while studying DNA extracts.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">38. The first cytokinin discovered was<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Zeatin<br>B) Kinetin<br>C) 6-BA<br>D) Zeatin riboside<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Kinetin was obtained from autoclaved herring sperm DNA.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">39. The main function of cytokinins is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Root elongation<br>B) Flower induction<br>C) Cell division<br>D) Fruit ripening<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins are also called \u201ccell division hormones.\u201d\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">40. In tissue culture, a high cytokinin to auxin ratio favors<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Root formation<br>B) Shoot formation<br>C) Callus initiation<br>D) Senescence<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins promote shoot differentiation, whereas auxins promote roots.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">41. Cytokinins delay<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Senescence<br>B) Flowering<br>C) Apical dominance<br>D) Dormancy<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins are also called anti-aging hormones as they delay leaf yellowing.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">42. Natural cytokinin found in maize kernels is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Kinetin<br>B) Zeatin<br>C) IBA<br>D) NAA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Zeatin is the most common natural cytokinin.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">43. Cytokinins are synthesized mainly in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Root tips<br>B) Shoot apices<br>C) Leaves<br>D) Flowers<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins are synthesized in root tips and transported upward via xylem.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">44. Which hormone promotes nutrient mobilization in plants?<br><\/mark><\/strong>A) Cytokinin<br>B) Auxin<br>C) Gibberellin<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins mobilize nutrients towards young leaves, fruits, and seeds.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">45. Cytokinins overcome apical dominance caused by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxins<br>B) Gibberellins<br>C) Ethylene<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins promote lateral bud growth, counteracting auxin effect.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">46. Which hormone is used to increase shelf life of vegetables?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Cytokinin<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins delay senescence and extend freshness of vegetables.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">47. Coconut milk contains<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxins<br>B) Cytokinins<br>C) Gibberellins<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Coconut milk is rich in natural cytokinins and used in tissue culture.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">48. High auxin to cytokinin ratio in tissue culture leads to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Callus<br>B) Root formation<br>C) Shoot formation<br>D) Senescence<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Root initiation requires high auxin relative to cytokinin.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">49. Cytokinins are chemically derivatives of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Indole<br>B) Purine (adenine)<br>C) Carotenoids<br>D) Amino acids<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins are adenine derivatives, e.g., kinetin, zeatin.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">50. Which pair of hormones acts antagonistically in bud growth regulation?<br><\/mark><\/strong>A) Auxin &amp; Cytokinin<br>B) Gibberellin &amp; Cytokinin<br>C) ABA &amp; Cytokinin<br>D) Ethylene &amp; Gibberellin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Auxin maintains apical dominance, while cytokinin promotes lateral bud growth.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">51. Which is the only gaseous plant hormone?<br><\/mark><\/strong>A) Cytokinin<br>B) Ethylene<br>C) Auxin<br>D) Gibberellin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene is a simple gaseous hydrocarbon (C\u2082H\u2084) acting as a plant hormone.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">52. Which hormone is responsible for fruit ripening?<br><\/mark><\/strong>A) Auxin<br>B) Ethylene<br>C) Cytokinin<br>D) Gibberellin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene regulates ripening of climacteric fruits like banana, mango, and tomato.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">53. Ethylene induces<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Seed dormancy<br>B) Flowering in pineapple<br>C) Apical dominance<br>D) Root elongation<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene induces synchronized flowering in pineapple plantations.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">54. Which hormone is used to ripen fruits artificially?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Ethylene<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Commercial ethylene or ethrel sprays are used to ripen fruits.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">55. Ethylene promotes<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Apical dominance<br>B) Senescence and abscission<br>C) Stem elongation<br>D) Phototropism<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene accelerates leaf fall, flower drop, and aging.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">56. Which hormone is used to increase latex yield in rubber plants?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Ethylene<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene stimulates laticifer activity in rubber.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">57. Ethylene promotes root initiation in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Tissue culture<br>B) Cuttings<br>C) Hydroponics<br>D) All of these<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene stimulates adventitious root formation.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">58. Triple response of ethylene includes<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Stem elongation, leaf expansion, senescence<br>B) Inhibition of elongation, stem swelling, horizontal growth<br>C) Apical dominance, bolting, parthenocarpy<br>D) Fruit ripening, seed dormancy, bolting<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  This response was first observed in pea seedlings.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">59. Ethylene production is highest in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Roots<br>B) Flowers<br>C) Ripening fruits<br>D) Leaves<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Climacteric fruits produce maximum ethylene during ripening.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">60. Ethylene is commercially available as<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) IAA<br>B) NAA<br>C) Ethrel<br>D) Zeatin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Ethrel (2-chloroethyl phosphonic acid) releases ethylene in plant tissues.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">61. Ethylene promotes female flowers in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Papaya<br>B) Cucurbits<br>C) Maize<br>D) Sugarcane<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene increases female flowers in cucumber and pumpkin.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">62. Ethylene enhances the rate of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Transpiration<br>B) Respiration<br>C) Photosynthesis<br>D) Mineral uptake<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene increases respiration during fruit ripening.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">63. Ethylene delays<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Abscission<br>B) Senescence<br>C) Flowering<br>D) None of these<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene promotes abscission and senescence, not delay them.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">64. Which hormone is called the \u201cstress hormone\u201d?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Abscisic acid<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  ABA accumulates under stress (drought, cold, salinity).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">65. Abscisic acid was initially called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Kinetin<br>B) Dormin<br>C) Zeatin<br>D) Florigen<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  ABA was named \u201cdormin\u201d due to its role in seed dormancy.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">66. Which hormone induces stomatal closure during drought?<br><\/mark><\/strong>A) Ethylene<br>B) Cytokinin<br>C) Abscisic acid<br>D) Auxin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  ABA prevents water loss by closing stomata.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">67. ABA is antagonistic to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Cytokinin<br>D) Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  GA promotes germination, ABA induces dormancy.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">68. ABA is synthesized mainly in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Young leaves<br>B) Root cap and mature leaves<br>C) Apical buds<br>D) Seeds only<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  ABA is produced in stressed leaves and transported via phloem\/xylem.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">69. Which hormone inhibits seed germination?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) ABA<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  ABA induces dormancy and prevents precocious germination.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">70. Which hormone increases seed dormancy in cereals?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) ABA<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  ABA maintains dormancy in wheat, rice, barley seeds.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">71. Which hormone promotes abscission of leaves and fruits?<br><\/mark><\/strong>A) Cytokinin<br>B) Gibberellin<br>C) Abscisic acid<br>D) IAA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  ABA accelerates senescence and abscission.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">72. ABA plays a major role in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Senescence<br>B) Flowering<br>C) Fruit ripening<br>D) Phototropism<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  ABA induces leaf aging and death.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">73. ABA inhibits<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Fruit ripening<br>B) Stomatal closure<br>C) Senescence<br>D) Dormancy<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  ABA generally delays fruit ripening unlike ethylene.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">74. Vivipary (precocious seed germination) is due to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) High ABA<br>B) Low ABA<br>C) High GA<br>D) Both B and C<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  Vivipary (as in mangroves) occurs due to low ABA and high GA.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">75. Which hormone acts as a \u201cuniversal inhibitor\u201d of plant growth?<br><\/mark><\/strong>A) Auxin<br>B) Cytokinin<br>C) Gibberellin<br>D) Abscisic acid<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  ABA inhibits growth and is termed the universal growth inhibitor.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">76. Which hormone is used to induce synchronized flowering in pineapple?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Ethylene<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene spray ensures uniform flowering in pineapple fields.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">77. Bolting in rosette plants (cabbage, lettuce) is induced by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Cytokinin<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Gibberellins elongate internodes, converting rosette habit to bolting.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">78. The pair of hormones that act antagonistically in seed germination is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxin &amp; Cytokinin<br>B) Gibberellin &amp; ABA<br>C) Ethylene &amp; Cytokinin<br>D) Auxin &amp; Ethylene<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  GA promotes germination, while ABA maintains dormancy.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">79. Callus differentiation in tissue culture depends on<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) High auxin concentration only<br>B) High cytokinin concentration only<br>C) Ratio of cytokinin to auxin<br>D) Ethylene concentration<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  High cytokinin:auxin \u2192 shoots; High auxin:cytokinin \u2192 roots.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">80. Florigen is a hypothetical hormone responsible for<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Phototropism<br>B) Flowering<br>C) Senescence<br>D) Parthenocarpy<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Florigen is the postulated mobile flowering signal in plants.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">81. Hormone mixture used in tissue culture for shoot regeneration<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) High auxin, low cytokinin<br>B) High cytokinin, low auxin<br>C) Equal auxin and cytokinin<br>D) Only gibberellin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins promote shoot development.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">82. Which hormone promotes femaleness in cucumber flowers?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Ethylene<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene increases female flowers in cucurbits.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">83. Which hormone is used in malting industry for brewing beer?<br><\/mark><\/strong>A) Cytokinin<br>B) Ethylene<br>C) Gibberellin<br>D) Auxin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  GA induces hydrolytic enzymes in barley grains during malting.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">84. Which hormone is used to increase fruit size in grapes?<br><\/mark><\/strong>A) Cytokinin<br>B) Gibberellin<br>C) Auxin<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  GA sprays increase bunch size and looseness of grapes.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">85. Seedless fruits in tomato and cucumber can be obtained by application of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxin<br>B) Cytokinin<br>C) ABA<br>D) Florigen<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Auxins induce parthenocarpy (fruit development without fertilization).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">86. Which hormone promotes senescence (aging) of leaves?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Cytokinin<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  ABA accelerates leaf yellowing and senescence.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">87. Which hormone is used as a weed killer in wheat fields?<br><\/mark><\/strong>A) Ethylene<br>B) 2,4-D (auxin)<br>C) Cytokinin<br>D) Gibberellin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  2,4-D selectively kills dicot weeds without harming monocot crops.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">88. \u201cRichmond Lang Effect\u201d (delay of leaf senescence) is caused by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Auxin<br>B) Cytokinin<br>C) Ethylene<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Cytokinins delay aging, keeping leaves green for longer.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">89. Which hormone induces opening of flowers in cotton, tobacco and tomato?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Ethylene<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene promotes flower opening in several crops.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">90. Apical dominance can be overcome by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) Application of gibberellin<br>B) Application of cytokinin<br>C) Removal of apical bud<br>D) Both B and C<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D <\/b><BR>\n<b>Explanation:<\/b>  Apical dominance is controlled by auxin; cytokinin or bud removal releases lateral buds.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">91. Which hormone promotes abscission of fruits under stress?<br><\/mark><\/strong>A) Cytokinin<br>B) ABA<br>C) Auxin<br>D) Gibberellin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  ABA accelerates abscission, especially under drought.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">92. Which hormone induces seed germination in barley by activating amylase?<br><\/mark><\/strong>A) Cytokinin<br>B) Gibberellin<br>C) Ethylene<br>D) Auxin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  GA activates aleurone layer to secrete amylase.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">93. Which hormone causes horizontal growth in dark-grown seedlings?<br><\/mark><\/strong>A) Ethylene<br>B) Auxin<br>C) Cytokinin<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>   Ethylene causes triple response, including horizontal growth.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">94. Vivipary (precocious germination in fruits) is due to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) High ABA<br>B) High Ethylene<br>C) Low ABA &amp; High GA<br>D) High Auxin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  In mangroves, reduced ABA and high GA cause seeds to germinate on plant.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">95. Which hormone is commercially used to ripen bananas?<br><\/mark><\/strong>A) Auxin<br>B) Ethylene<br>C) Cytokinin<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Ethylene chambers are used to ripen bananas and mangoes.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">96. Which hormone enhances resistance against drought by closing stomata?<br><\/mark><\/strong>A) Auxin<br>B) Ethylene<br>C) ABA<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  ABA induces stomatal closure to conserve water.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">97. Which hormone is used for inducing parthenocarpy in watermelon?<br><\/mark><\/strong>A) Auxin<br>B) Gibberellin<br>C) Cytokinin<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Gibberellin sprays induce seedless fruit development in watermelon.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">98. Which hormone promotes xylogenesis (formation of xylem)?<br><\/mark><\/strong>A) Auxin<br>B) Cytokinin<br>C) Ethylene<br>D) ABA<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>   Auxins promote differentiation of vascular tissues, especially xylem.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">99. Fruit drop in citrus orchards can be controlled by spraying<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ____________.<\/mark><\/strong><br><\/mark><\/strong>A) ABA<br>B) 2,4-D (auxin)<br>C) Ethylene<br>D) Cytokinin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Auxin sprays prevent premature fruit abscission.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">100. Which is called the \u201cuniversal growth inhibitor\u201d?<br><\/mark><\/strong>A) Cytokinin<br>B) ABA<br>C) Auxin<br>D) Gibberellin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Abscisic acid inhibits growth and is termed the universal growth inhibitor.\n <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>1. The first discovered plant hormone is ____________.A) GibberellinB) CytokininC) AuxinD) Abscisic acid Show Answer Answer: C Explanation: Auxin was the first plant hormone discovered through phototropism experiments by Darwin, and later isolated by Frits Went. 2. Who demonstrated that plant shoots bend towards light due to a chemical substance?A) Charles DarwinB) KurosawaC) Frits WentD)<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,1],"tags":[16561,16357,16352,16556,16133,16490,16154,16147,16158,16139,16553,16529,16515,16135,16560,16363,16368,16562,16566,16360,16359,16543,16559,16567,16551,16555,16355,16494,4029,5649,5652,5623,16533,16487,16366,16554,16512,16558,16548,16563,16358,16565,11005,16549,16265,16550,16532,16552,16542,16544,16557,16564,16546,16361,16547],"class_list":{"0":"post-12982","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-biology","7":"category-blog","8":"tag-aba-function","9":"tag-abscisic-acid","10":"tag-auxins","11":"tag-biology-for-competitive-exams","12":"tag-biology-mcqs","13":"tag-biology-practice-questions","14":"tag-biology-questions-and-answers","15":"tag-biology-quiz","16":"tag-biology-revision","17":"tag-biology-study-material","18":"tag-botany-concepts","19":"tag-botany-mcqs","20":"tag-class-11-biology-mcqs","21":"tag-competitive-exam-biology","22":"tag-cytokinin-function","23":"tag-cytokinins","24":"tag-ethylene","25":"tag-ethylene-function","26":"tag-functions-of-plant-hormones","27":"tag-geotropism","28":"tag-gibberellins","29":"tag-growth-and-development-in-plants","30":"tag-growth-regulation-in-plants","31":"tag-hormonal-control-in-plants","32":"tag-hormonal-regulation","33":"tag-hormone-action-in-plants","34":"tag-hydrotropism","35":"tag-important-biology-topics","36":"tag-mcqs-adda","37":"tag-mcqs-for-pc-psi-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","38":"tag-mcqs-for-pc-psi-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-examsin-kannada","39":"tag-mcqs-for-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","40":"tag-mcqs-with-answers-and-explanations","41":"tag-neet-biology-mcqs","42":"tag-phototropism","43":"tag-plant-biochemistry","44":"tag-plant-biology","45":"tag-plant-chemical-coordination","46":"tag-plant-growth-and-control","47":"tag-plant-growth-factors","48":"tag-plant-growth-regulators","49":"tag-plant-hormones-mcqs","50":"tag-plant-hormones-top-100-mcqs-with-answer-and-explanation","51":"tag-plant-movement","52":"tag-plant-physiology","53":"tag-plant-physiology-notes","54":"tag-plant-science-quiz","55":"tag-plant-signaling","56":"tag-plant-tissue-response","57":"tag-role-of-auxin-and-gibberellin","58":"tag-role-of-hormones-in-plants","59":"tag-science-mcqs","60":"tag-thigmotropism","61":"tag-tropic-movements","62":"tag-types-of-plant-hormones"},"_links":{"self":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12982","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/comments?post=12982"}],"version-history":[{"count":106,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12982\/revisions"}],"predecessor-version":[{"id":38156,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12982\/revisions\/38156"}],"wp:attachment":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/media?parent=12982"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/categories?post=12982"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/tags?post=12982"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}