Across
1
Form of thermal energy
3
Biological catalyst
6
Positive particle in nucleus
8
Tectonic landmass section
9
Smallest unit of an element
11
Tissue that contracts for movement
Down
2
Element found in all living things
4
Gas essential for breathing
5
Our home planet
7
Second lightest element
10
Disturbance that transfers energy
12
The Red Planet