Which of the following is(are) TRUE of
photoautotrophs?
a. They are responsible for the first concentration
of free oxygen in the atmosphere.
b. They are responsible for an early extinction of
most anaerobic organisms.
c. They are carbon-rich food baskets for
heterotrophs.
d. They are responsible for the presence of the
ozone layer of the atmosphere
e. All of these are true.
Answer: e
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Short tandem repeat sequences (STRs) can be used for DNA fingerprinting because ____.
A. they are expressed at different levels in individuals. B. they can be amplified by PCR. C. the number of repeats varies between individuals. D. they are found in different locations in individuals. E. their DNA sequence varies between individuals.
The fluid that enters vertebrate nephrons is called the filtrate. What is the source of the filtrate?
a. blood in capillaries b. urine c. lymphatic fluid d. cells of the kidney e. the loop of Henle
Succession happens because species in the habitat alter that habitat in ways that assist other species. There are three dynamic concepts that are of critical importance for succession to take place. They are
A. symbiotic relationships, facilitation, and aposematic coloration. B. competition, climax communities, and tolerance. C. establishment, coevolution, and competitive exclusion. D. establishment, facilitation, and inhibition. E. competition, inhibition, and coevolution.
Motility is the only digestive task of the
a. mouth. b. esophagus. c. stomach. d. duodenum. e. jejunum.