In the open ocean, tiny organisms called Choose...
perform photosynthesis. They are the primary producers in many
Choose...
that overlap to form a(n)
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.

primary producers in many

Explanation:

Plankton (fish eggs, larvae, microscopic crustaceans) are a diverse group of organisms at the base of the food chain in aquatic environments. Plankton are primarily found in the epipelagic or photic zone, the area in the open ocean from the surface down to 200 m (650 ft).

I hope this helped

i'd say that the moon rock is about 2.2 billion years old.