Countercurrent Exchange Is Evident in

question 72

Multiple Choice

Countercurrent exchange is evident in

• A) the flow of water across the gills of a fish and that of blood within those gills.
• B) the flow of blood in the dorsal vessel of an insect and that of air within its tracheae.
• C) the flow of air within the primary bronchi of a human and that of blood within the pulmonary veins.
• D) the flow of water across the skin of a frog and that of blood within the ventricle of its heart.
• E) the flow of fluid out of the arterial end of a capillary and that of fluid back into the venous end of the same capillary.

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Definitions:

Phototropism

The growth response of a plant in direction to a light source, enabling the plant to maximize light absorption for photosynthesis.

Thigmotropism

In plants, growth in a direction influenced by contact.

Gravitropism

Directional response to gravity.

Pollinator

An animal that facilitates pollination by moving pollen; an animal pollination vector.