what do scientists think about the common ancestor of whales and hippos?

a. The animal had two limbs.
b. The animal is still alive today.
c. The animal lived in water.
d. The animal lived millions of years ago.

d. The animal lived millions of years ago.

Scientists believe that the common ancestor of whales and hippos lived around 60 million years ago during the Eocene epoch. This animal was likely a small, land-dwelling mammal that eventually evolved into the diverse group of species we see today.