Why did the Greeks especially revered Zeus and Poseidon?

Why did the Greeks especially revered Zeus and Poseidon? Why did the ancient Greeks portray the gods as humans? What people believe in one god? Why don’t the Greeks believe in gods?

Zeus was considered the supreme god of Greece and was revered as responsible for everything that happens in the world of gods and people. The Athenians, being navigators, revered the god Poseidon, the patron saint of sailors and the ruler of the seas and oceans. The Greeks, emphasizing the special role of the gods in human life, portrayed them in human form. At that time, the Jews believed in one god. The ancient Greeks and their deities have gone and other gods and beliefs have come in their place, so modern Greeks do not believe in the departed gods.