The ability to taste the bitter chemical PTC is inherited as a simple dominant trait. In a population of 1000 biology students, 640 of them are PTC tasters. What proportion of this population are non-tasters?

The correct option is D 0.36

Phenylthiocarbamide (PTC) tasting is a trait governed by a pair of alleles, where dominant T is for tasting and recessive t is for non-tasting. The ability to taste the bitter chemical PTC is inherited as a simple dominant trait. TT and Tt are tasters and tt are non-tasters.

If the total population is of 1000, and 640 are tasters. It means that 360 are non-tasters.

So, the correct answer is option D.