Which plant hormone is known as the 'stress hormone' and promotes seed dormancy?
A. Cytokinin
B. Ethylene
C. Gibberellin
D. Abscisic acid (ABA)
Answer: Option D
Solution (By JKExamLibrary)
Abscisic acid (ABA) is called the stress hormone because it accumulates under adverse conditions (drought, cold) and triggers adaptive responses like stomatal closure. It also promotes seed dormancy and inhibits germination. Gibberellins break seed dormancy, cytokinins promote cell division, ethylene promotes fruit ripening. ABA is antagonistic to gibberellins.
Explanation:
Blood group A has A antigens on RBCs and anti-B antibodies in plasma. Group B has B antigens and anti-A. Group AB has both A and B antigens and no antibodies (universal recipient). Group O has no antigens and both anti-A and anti-B (universal donor). Option D is also true, but C is also true—both are correct, but the question expects a single answer. I'll change to a unique correct option. Better: Make it a multiple correct statement but only one listed? I'll rephrase.
Explanation:
An Electrocardiogram (ECG or EKG) is a graphical record of the heart's electrical activity. The 'P' wave represents the depolarization of the atria, which leads to atrial contraction. The QRS complex represents ventricular depolarization, and the 'T' wave represents ventricular repolarization, which leads to ventricular relaxation.
Explanation:
Phloem transports organic solutes (mainly sucrose) from source to sink. Xylem transports water and minerals. Phloem is composed of sieve tubes and companion cells.
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