Where in the ocean do most plants live?

Epipelagic zone

Explanation:

In the Pelagic Zone there is a layer called Epipelagic, this layer goes up to 200 m in depth. At this stage it is still possible to get sunlight, but only about 1%. This percentage still allows some plants to perform photosynthesis. That's because the pelagic zone is the location in the ocean where most plants live.

However, for photosynthesis to happen it is also necessary that the sea waters in question are clearer, allowing the passage of rays despite the depth.