Which of the following assist(s) in venous return to
the heart?
a. valves that prevent backflow
b. vasoconstriction during exercise
c. contraction of skeletal muscles alongside veins
d. pressure changes in the thorax during breathing
e. all of these
Answer: e
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Compared to uric acid, producing urea as the main form of nitrogenous waste requires ____
a. more energy and water b. less energy and water c. more energy and less water d. the same amount of energy and water e. less energy and more water
Chlamydia trachomatis causes
A. gonococcal urethritis. B. trachoma. C. dental caries. D. trachoma and nongonococcal urethritis.
Fisher's sex ratio model predicts a 1:1 female:male sex ratio. Why has this sort of system evolved?
What will be an ideal response?
Proteins consist of
(a) monosaccharides linked in chains. (b) amino acid units. (c) polysaccharide units. (d) condensed fatty acids.