The uppermost part of the oceans, as expressed by normal ocean waves, are in constant motion due to the effects of the:

A) wind
B) ultraviolet radiation
C) gravity
D) tides

Ocean Waves

Rhythmic movements of the water in oceans and seas, often caused by wind or geological factors.

Ultraviolet Radiation

A form of electromagnetic radiation with a wavelength shorter than that of visible light but longer than X-rays, capable of producing sunburn.

Tides

The regular rise and fall of sea levels caused by the gravitational forces exerted by the Moon and the Sun on the Earth's oceans.