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.
Actually, in the entire solar system, the planet with an atmosphere composed mostly of Nitrogen? Is Earth. We're composed of nitrogen (78%), oxygen (21%), and other miscellaneous gases (1%). All three of the planets you give for options are gas giants with primarily hydrogen-helium atmospheres. Neptune would be the coldest (about 55Â° Kelvin).