Across
1
Path of a planet around the sun
4
Disturbance that transfers energy
6
Tissue that contracts for movement
8
Magnetic metallic element
10
Ball of burning gas in space
11
Natural satellite of Earth
Down
2
Substance with pH above 7
3
Unit of energy
5
Icy body with a tail near the sun
7
Compound containing oxygen
9
Hottest planet in solar system
12
Curved glass that refracts light