Complete Question:
The body determines whether certain genes should be expressed or not. Sometimes genes are only turned on once or twice in a lifetime. Which example best illustrates this point?
A. milk-producing hormone after childbirth .
B. insulin after eating .
C. adrenaline when scared or in danger.
Correct Option:
The milk-producing hormone after childbirth is the example which best illustrates the above given point.
Option: A
Step-by-step explanation:
The development of mammalian glands occurs during pregnancy. After giving birth to a child the breast begins to grow in size. Just copious milk is generated after delivery, which is typically achieved with the help of milk hormone. Throughout pregnancy, the production of milk is hindered by the estrogen and progesterone that makes its way in the blood stream, which in effect prevents the secretion of prolactin from the pituitary gland, thereby making the mammary glands uncooperative. Thus the hormone for generation of milk after childbirth is not frequent in one's lifetime.