Question

What enables a whale to move its fins in the ocean?

Answer 1

I think the 'fin' here means the anterior flippers.

Explanation:

Flipper of dolphin and whale is just the forelimb, with same sets of bones as human hand. Then there are similar muscles like biceps and triceps to move the flipper.

Whale and dolphins may have a dorsal fin, which does not have a bony core but is made of fibrous connective tissue. Dorsal fin of killer whales may often collapse due to absence of bones and muscles.

Tail fin (also termed flukes) is also without bone.