Why does earth orbit the sun rather than any other body in the solar system? a) the mutual repulsions among all the planets hold earth in its orbit. b) the earth is closer to the sun than other bodies in the solar system. c) the sun is the most massive object; gravitational attraction is related to mass. d) the rotational motions of all the planets, including earth, cause them to remain in its orbit around the sun.

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.