Why are side effects important for a drug

Because if you take a drug normally without any side affects, you might get VERY sick.  ( DON''T TAKE DRUGS UNLESS YOUR DOCTOR GIVES YOU SOME)

Explanation:

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.