Question

why is it dark in the deep ocean?

Explanation:

Sunlight can't reach deep ocean. Water absorbs and scatters light. So deep ocean is dark.

Answer:

Sunlight cannot penetrate to great depths in the ocean. As light travels through water, it is absorbed and scattered by water molecules, suspended particles, and dissolved substances. The deeper you go, the less light remains, and beyond a certain depth (usually around 1000 meters or so), there is essentially no sunlight, making the deep ocean dark.