How do scientist use layers of rock to determine when the Great Oxidation event occured?

Using the concept of relative dating

Explanation:

Scientists use the concept of relative dating principles to determine when the Great Oxidation event occurred.

Relative dating is the process of placing ancient event in their proper time sequence based on the relationship between rock lithologies.

answer; ///i believe that the correct answer is (a) specialized cells)

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.