The great efficiency of gills is derived from
I-the countercurrent flow of water over the gills.
II-the blood within the gills.
III-increasing the temperature of the blood to the gills.

Question

Quizplus · Accepted Answer

The great efficiency of gills is primarily derived from the countercurrent flow of water over the gills (I) and the blood within the gills (II). This is because countercurrent flow allows for maximum diffusion of oxygen from the water into the blood, while the close proximity between the water and blood vessels within the gills increases the surface area available for oxygen exchange. Increasing the temperature of the blood to the gills (III) would actually be counterproductive, as this would lead to decreased oxygen uptake due to the decreased oxygen-carrying capacity of warmer blood.

The Great Efficiency of Gills Is Derived from