7. Nitrogen is a liquid °C. Nitrogen makes up % of the air that we breath. PLEASE ANSWER QUICK

Explanation is in the file

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Carbon has four electrons in its outermost shell, with these it forms covalent bond with other elements by sharing electrons with them.
The elements that made up the biological molecules react easily with carbon, giving rise to different types of macro molecules. Besides this, carbon is flexible and can conform to any shape whether linear, coiled, ring or ball form.