20. Played a major role in the formation of the modern earth's atmosphere. (5 Points)
Photosynthesis
Respiration
Both

The answer would be both

Explanation:

It is both because photosynthesis gave oxygen and respiration gave carbon dioxide that created a life cycle for plants and animals on earth! Have a great day and I hope this helped :D

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides