Consider the following statements about antibodies:
1. They are produced by T-lymphocytes.
2. They are also called immunoglobulins.
3. They specifically bind to antigens.
Which of the above is/are correct?
Explanation:
Antibodies are produced by B-lymphocytes (plasma cells), not T-cells. They are immunoglobulins that bind specific antigens. Thus, 2 and 3 are correct.
Explanation:
Abscisic acid (ABA) is a stress hormone that induces stomatal closure by causing efflux of K⁺ ions from guard cells, leading to loss of turgor, thereby reducing water loss during drought. Auxin and cytokinin promote growth, gibberellin stimulates stem elongation and seed germination. ABA also promotes seed dormancy and leaf senescence.
Explanation:
Thigmonasty (seismonasty) is a non-directional, rapid response to touch or vibration, exemplified by the drooping of Mimosa pudica leaves. Thigmotropism is directional growth towards/away from touch (e.g., tendrils). Phototropism is light-directed growth, geotropism gravity-directed.
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