Fill in the blank spaces with the correct information:
The Sun is in the center of Solar System and is composed mainly of the elements (1) and (2). The distance from the Earth to the Sun is also called (3). Many people dream about building a colony on Mars, but the atmosphere is primarily made of (4). We have discovered the (5) between Mars and
Jupiter, which contains millions of small objects. Jupiter has a total of (6) moons: The four largest moons are easily visible with a telescope and(7) is the closest and most active one. Uranus and Neptune are the outermost planets and it takes Neptune (8) years to complete one orbit around the Sun.