Thousands of years ago, giraffes with short necks were common within giraffe populations. Nearly all giraffe populations today have long necks. This difference could be due to:

Full question:

Thousands of years ago, giraffes with short necks were common within giraffe populations. Nearly all giraffe populations today have long necks. This difference could be due to

giraffes stretching their necks to keep their heads out of reach of predators

giraffes stretching their necks so they could reach food higher in the trees

a mutation in genetic material controlling neck size occurring in some skin cells of a giraffe

a mutation in genetic material controlling neck size occurring in the reproductive cells of a giraffe

This difference could be due to:a mutation in genetic material controlling neck size occurring in the reproductive cells of a giraffe

Explanation:

The primary short-necked forms contained large, mutable populations. Following the selection pressure of desiccations and leaf deficiencies, those changes with longer necks and forelegs sustained and repeated preferentially. In this procedure, throughout generations, these large mammals have occurred, being acclimated to their unique environment .

Lamarckian theory illustrated giraffe neck metamorphosis by showing that consistent stretching gradually extended their necks, and that they then moved on these propitious longer necks to their offspring. Environment andother variations created the extirpation of the eurasian giraffids,but various African species endured.

youre right there are