Maya poured four glasses of milk. the temperature and the amount of milk in each glass are shown

glass a: 20 grams of milk at 10 c
glass b: 50 grams of milk at 80 c
glass c: 20 grams of milk at 50 c
glass d 50 grams of milk at 80 c

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.