Question

4. Gills are an extension of -​

Answer 1

Explanation:

Gills are present in a variety of taxa. They are usually associated with the notopodial but may be present anywhere along the body; they are recognizable as thin-walled extensions from the body wall containing a vascular loop in which the two limbs of the loop are linked through capillaries.

Answer 2

Answer:

oxygen

Explanation:

here is your answer