The body region where a ciliary escalator helps to sweep microbes trapped in mucus away from that body site is the
A. respiratory tract.
B. skin.
C. digestive tract.
D. urinary tract.
E. eyes.
Answer: A
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Let R = red pigment and r = no pigment. In carnations, RR offspring make a lot of red pigment, rr offspring make no pigment and Rr offspring make a small amount of red pigment, thus appearing pink. Pink carnations are therefore an example of
A. codominance. B. incomplete dominance. C. epistasis. D. pleiotropy.
To test the hydrogen-bond hypothesis for reduced affinity of the heme group for carbon monoxide
when the heme is associated with polypeptide chains, the researchers used which of the following model systems?
a. Mutated rat myoglobin. b. Mutated rat hemoglobin. c. Myglobin gene isolated from a bacteria and introduced into sperm whale. d. Myglobin gene isolated from a sperm whale and introduced into a bacteria. e. Hemoglobin gene isolated from a sperm whale and introduced into a bacteria.
Which structure associated with the human heart contains oxygen-rich blood?
a. right atrium b. right ventricle c. pulmonary artery d. aorta e. superior vena cava
The rate of diffusion of molecules would be fastest in a cell with an
A. internal concentration of 40 percent and an external concentration of 35 percent in warm temperatures. B. internal concentration of 50 percent and an external concentration of 12 percent in cold temperatures. C. internal concentration of 45 percent and an external concentration of 50 percent in cold temperatures. D. internal concentration of 50 percent and an external concentration of 12 percent in warm temperatures.