Across
1
Particle of light
3
Group of similar cells
6
Unit of electric potential
8
Preserved remains of ancient life
9
Unit of heredity
10
Substance with pH above 7
11
Tissue that contracts for movement
Down
2
Nerve cell in the brain
4
Chemical element in table salt
5
Compound containing oxygen
7
Path of a planet around the sun
12
Element found in all living things