Across
1
Tectonic landmass section
4
Ball of burning gas in space
5
Fourth state of matter
8
Basic unit of life
9
Biological catalyst
10
Our home planet
11
Chemical element in table salt
Down
2
Center of an atom or cell
3
Curved glass that refracts light
6
Blocking of light by a celestial body
7
The Red Planet
12
Form of thermal energy