Across
1
Force that attracts objects together
3
Center of an atom or cell
4
Chemical element in table salt
9
Unit of electric potential
10
The Red Planet
12
Tissue that contracts for movement
Down
2
Blocking of light by a celestial body
5
Substance with pH below 7
6
Fourth state of matter
7
Glass that splits light into spectrum
8
Preserved remains of ancient life
10
Natural satellite of Earth
11
Naturally occurring inorganic solid