In the future, clean energy sources, such as solar power, may be used to create hydrogen fuel. true or false

i am going to guess that it is co2.

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.