Across
1
Fourth state of matter
4
Mass per unit volume
6
Blocking of light by a celestial body
7
Unit of force
10
The Red Planet
11
Naturally occurring inorganic solid
Down
1
Glass that splits light into spectrum
2
Preserved remains of ancient life
3
Curved glass that refracts light
5
Substance with pH below 7
8
Gas essential for breathing
9
Unit of heredity