Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle.
Neptune's atmosphere, like Jupiter's and Saturn's, is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen; it contains a higher proportion of ices such as water, ammonia, and methane.
Neptune is a giant planet. But it is not a gas giant like Jupiter or Saturn, it is an ice giant. Uranus and Neptune are called so because they are made from volatile chemical compounds which are heavier than Hydrogen and Helium and with freezing point greater than 100K. These substances are called ices. Some examples are water, ammonia and methane.