Consider the following scenario:

A drought hits the habitat of a semi-aquatic bird population. All ponds dry up, and fish populations decline. There are two groups of birds in the population that differ in leg length and diet. Long-legged birds eat fish, while short-legged birds eat insects. The drought has little effect on insect populations.


What is the main selective pressure in this scenario?

(1 point)

drought

leg length

insect population

fish population





There are two varieties in a population of squirrels: short tails and long tails. Long-tailed squirrels are better at jumping and balancing in trees. Scientists observe that over the span of 100 years, the proportion of the population with long tails increases from 10% to 60%. Which statement is most likely? (1 point)

The proportion of long-tailed squirrels may have increased due to increased food availability.

The proportion of short-tailed squirrels may have decreased due to decreased food availability.

The proportion of short-tailed squirrels may have decreased due to an increase in trees.

The proportion of long-tailed squirrels may have increased due to a decrease in trees.