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

Biology & Microbiology

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The fluid that enters vertebrate nephrons is called the filtrate. What is the source of the filtrate?

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