Purines and pyrimidines are components in the building block units of all ________.
A. nucleic acids
B. enzymes
C. polysaccharides
D. amino acids
E. carbohydrates
Answer: A
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Which part of the leaf stores toxic or unpalatable compounds in order to deter grazing herbivores?
a. cuticle b. stomata c. trichomes d. mesophyll
Several scientists, including Charles and Francis Darwin, Frits Went and others, demonstrated that auxins caused stems to bend toward light in a series of elaborate experiments. Went was the researcher who finally determined that bending of the stem toward light was a result of which mechanism?
A. Auxin concentration was equal on both sides (lighted and shaded) of the stem; however, the apical meristem responded to the presence of light. B. The transport of auxin to the shaded side of the plant stem stimulated stem elongation and a bending in the direction of the light. C. Light caused a reduction in auxin concentration and a reduction in stem elongation on the lighted side of the plant stem, and thus a bending in the direction of the light. D. A combination of positive phototropism and a negative gravitropism. E. The stems actually were responding to the agar blocks that had been used in the experiments.
Who am I? I typically have two flagella: one that wraps in a transverse groove and the other that
wraps in a longitudinal groove. a. green algae b. red algae c. euglenoids d. dinoflagellates e. brown algae
Molecules on the outside of the egg or sperm may trigger events that prevent their union if they are not from the same species. The type of isolating mechanisms displayed here is
A. morphological. B. biochemical. C. habitat. D. polyploidy.