In the female gametophyte, two cells flanking the egg secrete a ________ that guides the pollen tube's growth from the bottom of the style to the egg.
Fill in the blank(s) with the appropriate word(s).
polypeptide
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Sandra has spent quite a bit of time in the sun. UVA has led to mutations in some of her cells,
but this damage was repaired by __________.
a. DNA repair genes b. oncogenes c. tumor suppressor genes d. all of these
The most abundant class of antibody in the body, what antibody can function by neutralization, agglutination, opsonization, complement activation, and enhancement of natural killer cell activity?
A) IgM B) IgE C) IgG D) IgD E) IgA
If two organisms have similar rRNA sequences, you can conclude that they
A) live in the same place. B) evolved from a common ancestor. C) will have different G-C ratios. D) will both ferment lactose. E) mated with each other.
Which group of animals is the most recent to evolve?
A) reptiles B) amphibians C) invertebrates D) mammals