Question

What function is performed by human arms, forelimbs of dog and forelimbs of whales]?

Answer 1

human arms,forelimbs of dog and forelimbs of whale are homologous.
so function of human arms is to grasp something,forelimbs of dog-to walk and flippers of whale-swimming.

Answer 2

Homologous structure;Human arm,fore limb of dog and forelimb of whales

Explanation:

Homologous structures defines those structural part in an organism which bear similar structure and location but have different function in another organism.

Human hand, fore limb of dog and fore limb of whales have similar structure but their function differs as human arm is use to perform various physiological  function where as fore limb of dog helps them for locomotion and fore limb of whales help them for swimming in water.