Across
1
Tectonic landmass section
5
Form of thermal energy
7
Positive particle in nucleus
8
Basic unit of life
9
Compound containing oxygen
12
Group of similar cells
Down
2
Substance with pH above 7
3
Blocking of light by a celestial body
4
Our home planet
6
Path of a planet around the sun
10
Biological catalyst
11
Preserved remains of ancient life