Why is nitrogen important

is essential for all living things because it is a major part of amino acids, which are the building blocks of proteins and of nucleic acids such as DNA

Explanation:

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.

blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

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