The key chemical messenger responsible for increasing cardiac output when animals are exercising or under certain stresses is

A. epinephrine.
B. acetylcholine.
C. dopamine.
D. serotonin.
E. glutamate.


A. epinephrine.

Biology & Microbiology

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During photosynthesis in a leaf, sugars are loaded into the sieve tube by , followed by to move water which increases pressure.

A. osmosis; gravity B. gravity; active transport C. active transport; osmosis D. osmosis; facilitated diffusion E. facilitated diffusion; osmosis

Biology & Microbiology

The most complete fossil skeleton of an

australopith is that of

a. Australopithecus afarensis. b. Australopithecus africanus. c. Australopithecus habilis. d. Australopithecus sebida. e. Australopithecus garhi

Biology & Microbiology

Animals that maintain internal body temperature using heat generated by their own metabolism are called

A) endotherms. B) ectotherms. C) reptiles. D) amphibians.

Biology & Microbiology

Quaternary ammonium compounds ("quats") are used for

A) antisepsis. B) disinfection. C) sterilization. D) quantifying antimicrobial activity. E) both antisepsis and disinfection.

Biology & Microbiology