Ais a kind of lipid that can store energy for a long period of time. these lipids are made up of long chains of carbon and oxygen atoms bonded to a backbone structure.

fat

because A fat is a kind of lipid that can store energy for a long period of time. Fats are made up of long chains of carbon and oxygen atoms bonded to a backbone structure. This backbone structure is often glycerol.

Fats are important because they are a major source of energy. Since they contain even more carbon-hydrogen bonds than carbohydrates, fatty tissue has the ability to store energy for extended periods of time.

a- all cells come from pre-existing cells

ya the other dude is right