Question

fill in the blank question
objects in deep water appear dark because they are illuminated primarily by light

Explanation:

In deep - water, most of the visible light is absorbed or scattered by water molecules and suspended particles. Only blue light can penetrate relatively deeper. Objects in deep water are illuminated primarily by blue light. Since blue light has a shorter wavelength and is scattered more, the overall illumination is less intense, making objects appear dark.

Answer:

blue