English help - critical thinking

username5811975

Why are cats such good hunters? The answer lies in the taste buds. It is recognised by scientists that there are four basic tastes from which all flavours are composed: sour, bitter, salty and sweet. Interestingly, while most mammals are able to taste all of these, cats are unable to taste anything sweet. New research suggests that this is due to a genetic mutation which happened early in the evolution of the cat family, since all cats, both domestic and wild, share this characteristic. This mutation doubtless explains why cats evolved to be such good hunters, as, unlike other carnivores such as dogs who will eat fruits and berries if necessary, cats are limited to meat.

Which of the following is an assumption which underlies the above argument?
A An animal's behaviour is determined solely by its genetic make-up.
B Animals which enjoy fruits and berries will not be interested in hunting.
C If the mutation had occurred in dogs instead of cats they would now be the better hunters.
D Some fruits and berries do not taste sweet.
E The ability to taste sweet things was not lost as a result of cats' success as hunters.