Question

Select the correct answer from each drop-down menu.
Sharks, whales, and dolphins share similar
features such as body shape and the position of fins. However, sharks have gills for breathing, while whales and
dolphins have lungs. These differences indicate that the organisms share a common ancestor for
Whales also possess a vestigial pelvic bone. The presence of the pelvis bone may indicate that whales?

Answer 1

Answer:

The presence of the pelvis bone may indicate that whales once had hind limbs with which they used to walk on land over millions of years ago.

Explanation:

Whales lost their hind limbs during their evolution when they adapted completely to an aquatic life. Girdles are bones which allow limbs to get attached to the axial skeleton. No hind limbs means pelvic girdle bones are not anymore needed in whale.

Both whales and dolphins have pelvic (hip) bones, evolutionary remnants from when their ancestors walked on land more than 40 million years ago. Common wisdom has long held that those bones are simply vestigial, slowly withering away like tailbones on humans.