Across
1
Hottest planet in solar system
4
Gas essential for breathing
5
Push or pull on an object
6
Natural satellite of Earth
10
Second lightest element
11
Tissue that contracts for movement
Down
2
Particle of light
3
Absolute temperature scale unit
7
Path of a planet around the sun
8
Group of similar cells
9
Amplified beam of light
12
Compound containing oxygen