T cells can only be activated by ____

a. antigens presented by other cells
b. apoptosis
c. memory cells
d. plasma cells
e. complement proteins


ANSWER: a

Biology & Microbiology

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Connell studied two barnacle species, Balanus balanoides and Chthamalus stellatus. Where these species coexist,

____.

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Crossing over is one of the most important

events in meiosis because a. it produces new combinations of alleles on chromosomes. b. homologous chromosomes must be separated into different daughter cells. c. the number of chromosomes allotted to each daughter cell must be halved. d. homologous chromatids must be separated into different daughter cells. e. all of these reasons are true

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Four features help define __________: a notochord, a dorsal hollow nerve cord, a pharynx with gill

slits, and a tail extending past the anus. Fill in the blank(s) with the appropriate word(s).

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Slow-twitch muscle fibers have many mitochondria and

produce ATP using __________. a. aerobic fermentation. b. aerobic respiration. c. anaerobic muscle recovery. d. anaerobic fermentation. e. none of these.

Biology & Microbiology