5. The atmosphere of early Earth is unlike today's atmosphere. A. When did oxygen first appear in Earth's early atmosphere? (3 points)

B. What factor caused the appearance of oxygen? (3 points)

C. What is one form of evidence used to support this theory? (4 points)

it's 5

Explanation:

today's atmosphere we enjoy today is radically different from the atmosphere that formed with the earth billions of years ago.

wheres the options ? : (

explanation:

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