What is the explanation for why B cells come in so many different types that can produce so many different antibodies?
A) B cells can regulate shape to match the antigen.
B) The genome of B cells is much larger than other body cells.
C) B cells can recombine their genes with T cells.
D) B cells can recombine their genes with the pathogen.
E) B cells have gene fragments that can shuffle or recombine.
Answer: E
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Which of the following helminths is correctly paired with its portal of entry?
A. Ascaris lumbricoides - enters through the skin B. Taenia solium - eggs or larvae can be ingested C. Enterobius vermicularis - sexual transmission D. Schistomoma species - carried by an insect vector into human
Of the following, which is the first explanation
of a problem? (It is sometimes called an "educated guess.") a. principle b. law c. theory d. fact e. hypothesis
For sexually reproducing organisms, a species
consists of a. individuals sharing a habitat. b. a group of reproductive females. c. populations that have the potential to interbreed and produce fertile offspring. d. individuals that have the same nutritional requirements. e. individuals in the same geographical range with similar ecological requirements.