Question

explain how the single circulation respiratory system occurs in fish .​

Answer 1

Answer:

Gaseous exchange happens within the gills, and the oxygenated blood from the gills is circulated throughout the body. On the other hand, in mammals, the deoxygenated blood enters the heart, from where it is pumped into the lungs for oxygenation. ... Unlike humans, the four parts of a fish heart do not form a single organ.

Explanation:

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Answer 2

Gaseous exchange happens within the gills, and the oxygenated blood from the gills is circulated throughout the body. On the other hand, in mammals, the deoxygenated blood enters the heart, from where it is pumped into the lungs for oxygenation.