Across
1
Unit of energy
4
Natural satellite of Earth
5
Curved glass that refracts light
8
Reddish electrical conductor
10
Tissue that contracts for movement
11
Group of similar cells
12
Magnetic metallic element
Down
2
Gas essential for breathing
3
Unit of heredity
5
Amplified beam of light
6
Fourth state of matter
7
Compound containing oxygen
9
Blocking of light by a celestial body
13
Chemical element in table salt