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 .

Hello. Giraffes with longer necks survive compared to those with shorter necks because of natural selection. Over time, natural selection favors the traits that would make a species thrive better in the environment. Giraffes with short necks won't have access to that much food compared to those with long necks thus they eventually died out.

ANSWER: natural selection.

The answer is observations and interpreting.