Which of the following statements accurately explains how earth’s atmosphere supports life?
a. earth’s atmosphere contains 78 percent oxygen, which is essential for life.
b. earth’s atmosphere contains 21 percent oxygen, which many life forms need to
survive.
c. earth’s atmosphere contains more oxygen than carbon dioxide.
d. earth’s atmosphere contains carbon dioxide, which all life forms breathe in.

the answer is B.

Explanation:

you may have thought that the answer is a but that is false information and C. and D. are completely wrong

B  i know because i looked it up and my first answer was wrong

answer by yourhope:

answer is

human impact on the environment can be seen in the deterioration of the !

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c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.