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
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Connell studied two barnacle species, Balanus balanoides and Chthamalus stellatus. Where these species coexist,
____.
a. the realized niche of Balanus is smaller than its fundamental niche due to competition by Chthamalus b. the realized niche of Balanus is larger than its fundamental niche due to competition by Chthamalus c. the realized niche of Chthamalus is smaller than its fundamental niche due to competition by Balanus d. Balanus' fundamental niche includes all of Chthamalus fundamental niche e. the realized niche of Balanus is about equal to its fundamental niche
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
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).
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.