  Since 990 is divisible by ten, the answer is 990. If you were rounding off 994 the answer would also be 990. If you were rounding off 995, the answer would be 1,000.
Jupiter is the largest and most massive planet in the solar system. It was named after the chief Roman god. It is a gas giant composed of liquid and gaseous matter, and has many moons. Some of the storms in its atmosphere have lasted hundreds of years.
Composed predominantly of hydrogen and helium, the massive Jupiter is much like a tiny star. But despite the fact that it is the largest planet in the solar system, the gas giant just doesn't have the mass needed to push it into stellar status.The surface of Jupiter.he atmosphere of Jupiter is 90 percent hydrogen. The remaining 10 percent is almost completely made up of helium, though there are small traces of other gases inside. These gases pile on top of one another, forming layers that extend downward.