Assertion (A) and Reason (R) follow. Select the right choice:
Assertion (A): Population explosion happens when death rates drop sharply while birth rates stay elevated.
Reason (R): Changes in societal reproductive patterns occur immediately with healthcare advancements.

Correct Answer: Option "A true, R false"

Explanation:

1. Analysis of Assertion (A):

Assertion (A) states that a population explosion happens when death rates drop sharply while birth rates stay elevated. This statement is true. A population explosion occurs primarily due to a significant gap between birth rates and death rates. When healthcare, sanitation, and living standards improve, mortality rates (especially infant mortality) decline rapidly. However, if the birth rate remains high during this period, the rate of population growth increases dramatically, leading to a population explosion.

2. Analysis of Reason (R):

Reason (R) states that changes in societal reproductive patterns occur immediately with healthcare advancements. This statement is false. Societal reproductive patterns, social norms, family planning practices, and cultural preferences regarding family size change gradually over time. While healthcare advancements can rapidly reduce death rates, behavioral and cultural shifts regarding fertility and birth control lag behind, taking decades or generations to adapt.

Conclusion:

Since Assertion (A) is correct and Reason (R) is incorrect, the right choice is A true, R false.