Across
1
Tissue that contracts for movement
4
Path of a planet around the sun
6
Fourth state of matter
7
Unit of electric potential
8
Unit of energy
10
Unit of heredity
Down
2
Group of similar cells
3
Preserved remains of ancient life
4
Compound containing oxygen
5
Reddish electrical conductor
9
Form of thermal energy
11
Blocking of light by a celestial body
12
Center of an atom or cell