Question

________ are the source of all light in space. moons stars planets the planets, moons, and sun are part of the ______. planet alliance solar system intergalactic space force the solar system is held together by ______. mass energy gravity the sun is mostly ________. oxygen and water helium and hydrogen nitrogen and...

Explanation:

1. Stars generate their own light via nuclear fusion, while moons and planets only reflect light.
2. The sun, planets, and their moons form the solar system; the other options are fictional.
3. Gravitational force between the sun and celestial bodies keeps the solar system bound.
4. The sun is a star composed primarily of hydrogen (about 73%) and helium (about 25%).

Answer:

1. stars
2. solar system
3. gravity
4. helium and hydrogen