Across
1
Center of an atom or cell
7
Substance with pH below 7
8
Group of similar cells
9
Curved glass that refracts light
10
Measure of matter in an object
11
Tectonic landmass section
Down
2
Mass per unit volume
3
Basic unit of life
4
Biological catalyst
5
Preserved remains of ancient life
6
Hottest planet in solar system
9
Amplified beam of light
11
Glass that splits light into spectrum
12
Icy body with a tail near the sun