Which of the following is considered a keystone species within Yellowstone National Park?
a. beavers
b. wolves
c. elk
d. cottonwood
b. wolves
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When scientists experimentally simulated conditions near a hydrothermal vent, _____ appeared within a week
a. cells b. nucleic acids c. hydrocarbons d. amino acids e. lipid membranes
Reshaping the cornea using lasers is often used to treat
a. astigmatism. b. retinoblastoma. c. myopia. d. glaucoma. e. cataracts.
The most likely explanation for any mass-extinction event is
A) a gradual increase in global temperature. B) coevolution of predator and prey species. C) loss of genetic diversity due to inbreeding. D) human activity. E) rapid environmental change.
Development occurs:
A) only in non-dividing cells. B) only during growth of the organism. C) throughout the life of the organism. D) only in animals.