Suppose that out of a population of 100 indiviuduals 25 could not taste PTC The tasters in this population only

Question

suppose that out of a population of 100 indiviuduals, 25 could not taste PTC. The tasters in this population only

married and reproduced with other tasters. What evolutionary force is this an example of? ( help I’m not sure if this question involves going the math of hardy weinburg)

Science