Question

where is the greatest amount of the worlds carbon found?
atmosphere
seafloor sediments
ocean
plants and animals

Explanation:

The ocean stores a vast amount of carbon through processes like absorption of CO₂ from the atmosphere and carbon cycling within marine ecosystems. Seafloor sediments also contain significant carbon, but the ocean (including its water column and associated biological and chemical processes) holds the greatest amount compared to the atmosphere (which has less carbon in terms of total quantity in the global carbon cycle), and plants and animals (which have a much smaller carbon - holding capacity relative to the ocean).

Answer:

ocean