If cells were a school building, the cell membrane would most likely be represented by which of the following? А
intercom
B
lockers
С
teachers and students
D
walls and doors

what's the rest of the question

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.