  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.
Atmosphere and Magnetic Field. The mass of Jupiter's atmosphere is composed of 75% hydrogen and 25% helium. It is crisscrossed with dark and light colored stripes that are caused by winds in the upper atmosphere.These winds can be as fast as 400 miles per hour.The lighter levels are called zones and are made of frozen ammonia crystals.he mass of Jupiter's atmosphere is composed of 75% hydrogen and 25% helium. It is crisscrossed with dark and light colored stripes that are caused by winds in the upper atmosphere.