What is the role of a countercurrent exchange?
a. It allows for an efficient exchange.
b. It reduces a concentration gradient.
c. It allows ventilation to occur more rapidly.
d. all of these
A
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A tariff is a
a. tax on exports. b. penalty imposed on exporters who export a greater quantity than the quota allows. c. penalty imposed on importers who import a greater quantity than the quota allows. d. tax on imports.
The movement of large molecules or large quantities of molecules into a cell is accomplished through ________; movement of these molecules out of the cell is accomplished through ________
Fill in the blank(s) with correct word
The ________ valve is between the right ventricle and the pulmonary artery
A) semilunar B) tricuspid C) bicuspid D) atrioventricular
Which of the following factors should make females the "choosier" sex?
a. Eggs are expensive and rare compared to sperm. b. Females tend to invest more time and energy in gestation time and/or brood care. c. Female quality never plays a role in male mating decisions. d. Males and females show about the same variation in quality. e. A and B.