You are presented with the quiz "The pull of what on the Earth's oceans cause the tides?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "the gravitational pull of the Moon on Earth 's oceans causes the tides" and "planetary moons are natural satellites". So, what's the best answer to the question?

Choices:
I. A yellow star
II. Time and energy
III. energy of moving objects
IV. A natural satellite
V. flow of electrons
VI. An artificial satellite
VII. A red star
VIII. hydrogen and oxygen
Answer:
IV.