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 a little effect on insect populations.
what is the main selective pressure in the scenario?
a fish population
b drought
c leg length
d insect population