Biological evidence of the age of the earth includes .

Biological evidence of the age of the earth includes radioactive dating of rocks, fossil evidence, comparative anatomy and molecular clocks

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.

thats not a question