Final

2. the antiparticle of the proton
5. the SI base unit of thermodynamic temperature.
8. average density of matter required for the Universe to just halt its expansion.
10. of the same or a similar kind or nature.
11. nonluminous material in space.
13. the speed of light

1. a particle representing a quantum of light or other electromagnetic radiation.
2. consisting of antiprotons, antineutrons, and positrons.
3. having a physical property has the same value
4. When a body that is emitting radiation
6. the era where the was hot and dense.
7. basic building block of chemistry.
9. he science of the universe.
12. the era that started when the gravitational effect