An ? helix is formed by hydrogen bonds between:
A. nonpolar and polar R groups.
B. positively charged and negatively charged R groups.
C. the carbonyl oxygen and the amide nitrogen of alternate amino acids.
D. the carbonyl oxygen and the amide nitrogen of every third amino acid.
E. the carbonyl oxygen and the amide nitrogen of every fourth amino acid.
E
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The cell wall is a common feature to
A. prokaryotic cells only. B. plant cells only. C. animal cells only. D. prokaryotic and plant cells. E. prokaryotic, plant, and animal cells.
Darwin's observation of vastly different species living in similar island environments led him to conclude that each
population had arisen separately from existing species on these islands, since the geographic isolation prevented migration of species from the mainlands. This scenario is an example of ____.
a. biogeography b. plate tectonics c. comparative morphology d. morphological convergence e. homologous structures
Increasing density does not affect the body mass of individual organisms
Indicate whether the statement is true or false
A renewable energy source that taps into heat produced deep below ground is called
A) hydroelectric. B) geothermal. C) solar. D) "subterranean" wind. E) fossil fuel.