Across
1
Amplified beam of light
4
Blocking of light by a celestial body
5
Group of similar cells
10
Natural satellite of Earth
11
Biological catalyst
Down
2
Reddish electrical conductor
3
Basic unit of life
6
Nerve cell in the brain
7
Unit of heredity
8
Unit of force
9
Mass per unit volume
12
Tissue that contracts for movement