Question

diatoms are responsible for only a small fraction of photosynthetic co₂ fixation. move using flagella. are primary producers. form cell walls containing calcium carbonate. are likely to be found in the deep ocean.

Explanation:

Diatoms are single - celled algae that perform photosynthesis, making them primary producers. They contribute significantly to photosynthetic CO₂ fixation, not a small fraction. They do not move using flagella. Their cell walls contain silica, not calcium carbonate. They are found in the upper layers of water bodies where there is light for photosynthesis, not the deep ocean.

Answer:

are primary producers.