  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.
The Atmosphere of Jupiter. Jupiterâs atmosphere is the largest in the Solar System. Molecular Hydrogen and Helium make up most of its atmosphere as well as small amounts of ammonia, methane, hydrogen sulfide and water. Gases such as nitrogen sulfur, noble gas and oxygen can also be found in the planet. The gaseous part of the atmosphere slowly transitions into the liquid part of the planet.