In fish, blood flows in a direction opposite to the flow of water over the gills in a process known as:
a. concurrent exchange.
b. countercurrent exchange.
c. crosscurrent exchange.
d. exhalation.
e. diffusion
B
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Which of the following is a disaccharide?
A) galactose B) lactose C) fructose D) glucose E) amylose
Of the following, which is used to inhibit specific enzymes in the treatment of many bacterial and viral diseases?
A) substrate analogues B) noncompetitive inhibitors C) intercalating agents D) nitrous oxide E) X-rays
A species is composed of
a. related organisms. b. a group of reproductive females. c. populations that have the potential to interbreed and produce fertile offspring. d. organisms located in the same habitat. e. all males and females in the same geographical range with the same ecological requirements.
Light levels in the _____ are too low to support photosynthesis.
Fill in the blank(s) with the appropriate word(s).