Life Cycles of Stars

3. The element formed as a result of nuclear fusion in stars.
6. A giant cloud of gas and dust in space where stars are born.
8. The stable phase in a star's life when nuclear fusion of hydrogen occurs in its core.
11. The early stage of a star's formation, where gravity causes the nebula to collapse and heat up.
12. The extremely dense core left behind after a supernova, composed mostly of neutrons.
13. A phase in the life of a massive star before it goes supernova.
14. A small, dense, hot core left after a red giant sheds its outer layers.

1. The primary fuel for nuclear fusion in a star's core.
2. The process where hydrogen nuclei combine to form helium, releasing energy in stars.
4. The cold, dark remnant of a white dwarf after it has cooled completely.
5. A region of space with gravity so strong that not even light can escape.
7. A late stage in a star's life when it expands and cools after using up its hydrogen fuel.
9. A massive explosion that occurs when a star exhausts its nuclear fuel and collapses.
10. The force responsible for the formation and collapse of stars.