Across
1
Biological catalyst
5
Measure of matter in an object
6
Nerve cell in the brain
8
Smallest unit of an element
9
Amplified beam of light
11
Disturbance that transfers energy
12
Preserved remains of ancient life
13
Positive particle in nucleus
Down
2
Icy body with a tail near the sun
3
Push or pull on an object
4
The Red Planet
5
Tissue that contracts for movement
7
Hottest planet in solar system
10
Ball of burning gas in space