Compare the structure and lifestyle of a seal and a whale. What are their similarities and differences?

Seals live in the water, but go to land to rest, moult and breed with feeding. They have adapted to aquatic life and cold climates. The body is smooth, streamlined. The neck is almost undeveloped. The five-toed limbs were transformed into flippers. For swimming, the hind limbs, and for crawling, the front.
Whales have a streamlined torpedo body shape. The head is motionlessly connected to the body, blending smoothly into the tail. The forelimbs have become flippers. The hind limbs are not developed. A powerful tail is used for movement, which ends with a two-lobed fin. They are arranged vertically. Breathe atmospheric air. They also feed with milk, but in the water.