Its height increases. Its height decreases. Its length shortens. It crests.
I gave my students this multiple choice question: When the velocity of an ocean wave decreases as it approaches a shore, what happens to the wave?

Only one answer is correct among these 4 choices:
- Its height increases.
- Its height decreases.
- Its length shortens.
- It crests.

Could you tell me which one is correct?

Its height increases.