Keystone species are those that ________
a. modify the pioneer environment, allowing subsequent stages in succession to occur
b. after introduction, become established and disruptive to the native structure of a community
c. have a disproportionate effect on a community relative to their abundance
d. provide the photosynthetic plant base necessary to all communities
c
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Which of the following gives the correct rank order for relative energetic cost (most to least) of the primary nitrogenous wastes used by different animals?
A. ammonia ? urea ? uric acid B. uric acid ? urea ? ammonia C. urea ? uric acid ? ammonia D. ammonia ? uric acid ? urea E. urea ? ammonia ? uric acid
The three components of the female reproductive system that are required for successful reproduction are the eggs,
____________________, and ____________________. Fill in the blank(s) with the appropriate word(s).
Antisense nucleic acids interfere with protein synthesis
Indicate whether the statement is true or false
Which of the following sets of characteristics describes the highest level of threat potential from biological weapons?
A) a waterborne toxin that is easily introduced into public water supplies and does not replicate in humans B) a pathogen of livestock transmitted by contact with infected animals but not infected people C) a human pathogen easily produced as an aerosol and transmissible by respiratory aerosols D) a pathogen of wheat that could be delivered using crop dusters E) a microbe that can be introduced into food during packaging and withstands refrigerator temperatures but not typical cooking temperatures