Which best explains how the ocean is the most diverse ecosystem

It receives nutrients from land carried by rivers and upwelling.

Explanation:

An ecosystem is a system consisting of various organisms (for example, animals and plants) that interact in a medium (for example, a forest). The marine ecosystem is the system where organisms interact in the oceans; it is composed of marine animals such as fish or turtles, aquatic plants, and many single-celled organisms.

Upwelling is the process by which surface water is pushed by the wind away from the shore, and deep water rises.

Through this movement of seawater, the entire ecosystem receives nutrients from the earth, and the living beings of the ecosystem are nourished, this helps to the proliferation of different types of organisms, for example, some organisms live on the surface, and others live in the depths.

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