Why do fish have gills

Like us, fish also need to take in oxygen and expel carbon dioxide in order to survive. But instead of lungs, they use gills. ... As the fish opens its mouth, water runs over the gills, and blood in the capillaries picks up oxygen that's dissolved in the water.

step 1: replication fork formation.

step 2: primer binding.

step 3: elongation.

step 4: termination.

explanation:

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i think its white blood cells

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