71. Which of the following plant hormones inhibits growth and promotes dormancy?
(a) Auxin
(b) Gibberellin
(c) Cytokinin
(d) Abscisic acid
Answer:
(d) Abscisic acid
Explanation:
Abscisic acid is a plant hormone that functions as a growth inhibitor, promoting seed dormancy and the wilting and falling of leaves.
72. The electrical impulse travels in a neuron in the following direction:
(a) Axon $\rightarrow$ Cell body $\rightarrow$ Dendrite
(b) Dendrite $\rightarrow$ Cell body $\rightarrow$ Axon
(c) Dendrite $\rightarrow$ Axon $\rightarrow$ Body
(d) Axon $\rightarrow$ Dendrite $\rightarrow$ Cell body
Answer:
(b) Dendrite $\rightarrow$ Cell body $\rightarrow$ Axon
Explanation:
Electrical signals in a neuron are received by the dendrites, pass through the cell body (soma), and travel down the axon to the axon terminals.
73. Which hormone is released into the blood in large amounts during emergency situations (fight or flight)?
(a) Thyroxin
(b) Insulin
(c) Adrenaline
(d) Progesterone
Answer:
(c) Adrenaline
Explanation:
Adrenaline (epinephrine) is secreted by the adrenal glands during stress or emergencies, preparing the body for a “fight or flight” response.
74. A small portion of the oviduct is removed or tied is called:
(a) Vasectomy
(b) Tubectomy
(c) IUCD
(d) Oral pills
Answer:
(b) Tubectomy
Explanation:
Tubectomy is a surgical method of female sterilization where a small part of the fallopian tube (oviduct) is tied and cut to prevent the egg from meeting the sperm.
75. Vegetative propagation by leaves is found in:
(a) Potato
(b) Ginger
(c) Bryophyllum
(d) Rose
Answer:
(c) Bryophyllum
Explanation:
Bryophyllum propagates vegetatively through its leaves; buds produced in the notches along the leaf margin fall to the soil and develop into new plants.
