Select the correct answer from each drop-down menu. Giraffes evolved over many generations to have long necks. Giraffes that had longer necks were more likely to survive than giraffes with shorter necks because they had better access to food. This is an example of
.

Giraffes are also vertebrates, like humans. In fact, despite their different neck sizes, humans and giraffes have exactly seven vertebrae bones in their neck. This similarity suggests human and giraffe necks are
.