What are the locomotory organs of fish?

The tail and the caudal fin are the chief locomotory organs of fish and are used for rapid swimming during which tail is lashed from side to side by "alternate contraction and relaxation" of the myomeres on the two sides of the vertebral column.

Explanation:

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.