Will mark brialiest how do the planets venus and neptune differ in terms of atmospheric composition?

The atmosphere of Venus is mostly carbon dioxide, 96.5% by volume. Most of the remaining 3.5% is nitrogen. Early evidence pointed to the sulfuric acid content in theatmosphere, but we now know that that is a rather minor constituent of theatmosphere. 

The atmosphere of Neptune consists mainly of hydrogen and helium, but about 2.5-3% of the atmosphere is methane. Like Uranus, clouds in Neptune's atmosphere are composed of crystals of methane.

He should put sand around the spill in order to contain it so that it won't spread