Erection occurs when
A. the spongy erectile tissue of the penis becomes engorged with blood.
B. the veins flowing out of the penis vasoconstrict.
C. the arteries of the penis vasodilate.
D. nitric oxide is released.
E. All of these events occur to promote an erection.
E. All of these events occur to promote an erection.
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Normal flora in the duodenum are
A) similar to the microflora in the stomach. B) dominated by aerobic organisms. C) tolerant to alkaline environments. D) tolerant to high salinity.
In the Olestra experiment conducted by researchers at the Johns Hopkins University School of Medicine, the people
who ate the Olestra potato chips were the ____.
a. experimental group b. control group c. research group d. hypothetical group e. independent group
Explain the idea of transgenic animals as "bioreactors."
What will be an ideal response?
Which of the following is correct with respect to the amino acid composition of proteins?
A) Larger proteins have a more uniform distribution of amino acids than smaller proteins. B) Proteins contain at least one each of the 20 different standard amino acids. C) Proteins with different functions usually differ significantly in their amino acid composition. D) Proteins with the same molecular weight have the same amino acid composition. E) The average molecular weight of an amino acid in a protein increases with the size of the protein.