Suppose that two mosquito populations are being studied. The populations differ in their choice of the water in which they choose to lay their eggs. One population is urban and avoids laying eggs in water treated with insecticides, which are heavily used in urban areas. What difference between the populations would provide the best evidence that this preference is due to ultimate causes?

(A) A genetic difference
(B) A difference in preference for insecticide-free water
(C) A difference in the mosquito’s ability to sense insecticide levels
(D) A difference in taste receptors

(C) A difference in the mosquito’s ability to sense insecticide levels

Explanation:

In urban places, insecticides are widely used to fight insects such as mosquito. Some of the insecticides are normally poured in stagnated water  to kill mosquito larvae.

In the situation where two mosquito populations differ in their choice of water which they choose to lay their eggs. It shows one population has more ability to sense insecticide levels.

The other population has less ability that what causes it to lay their eggs in water treated with insecticide. Their larvae will be killed by the pesticide when they hatch.