Bees collect pollen from flowers. This is the fine powder of the stamens. If a bee visits a flower, they 're covered with pollen. They wipe with their feet all the pollen in their mouths and chew them into balls. That they put onto their hind legs in “pollen basket". Thus they fly to their home. Where the pollen is stored in the combs.
Bees also collect nectar, a kind of sweet juice that the flower separate to attract insects. The bees suck the nectar. The nectar comes in their honey stomach. Once in their homes the workers give the nectar to the workers who store it in combs. The workers will ensure that there is a constant flow of air into the hive, so the water in the nectar evaporates. After this 'dehydration' there is only about 18% moisture remained in the nectar and honey. To save the honey the workers seal the cells with a wax lid.
Water they use to prepare the feed for the larvae and, in the summer to drop the temperature in the dwelling.