Question

year before the drought and one year after the drought.
which of the following claims is best supported by the data in the figure?
a only individuals with certain traits could survive and reproduce after the drought, which led to a decrease in the genetic diversity of the populations.

b only individuals that developed mutations that enabled them to adapt to the drought conditions survived, which led to a decrease in the genetic diversity of the populations.

c the population with the most genetic diversity before the drought was best adapted to the drought conditions and as a result was the most genetically diverse population after the drought.

d the populations evolved to adapt to the drought conditions, which led to an increase in the genetic diversity of the populations.

Explanation:

• Option A: In natural selection, after a drought (a selective pressure), only individuals with traits favorable for survival/reproduction (certain traits) remain. This reduces genetic diversity as only a subset of traits (and their associated genes) persist.
• Option B: Mutations are random and not all adaptations come from new mutations during the drought; pre - existing favorable traits also matter. So this is incorrect.
• Option C: If a population had the most genetic diversity before, after selection (drought), only the favorable traits (a subset) would remain, so genetic diversity should decrease, not stay the most diverse.
• Option D: Drought - driven natural selection typically reduces genetic diversity (as only some traits are favored), not increase it.

Answer:

A. Only individuals with certain traits could survive and reproduce after the drought, which led to a decrease in the genetic diversity of the populations.