10. Which planet was first discovered by a telescope? A. Neptune C. Saturn B. Jupiter D. Uranus 11. Mercury, Venus, Earth, and Mars are called A. Jovian Planets B. Outer Planets C. Inner Planets D. Gas Giants 12. What do we call Jupiter, Saturn, Uranus, and Neptune? A. Gas Giants C. Outer Planets B. Inner Planets D. Terrestrial Planets C. Outer Planets 13. Which planet is closest to the Sun? A. Mars C. Neptune B. Mercury D. Venus​