Across
1
Disturbance that transfers energy
4
Tissue that contracts for movement
8
Unit of power
9
Infectious microscopic agent
10
Our home planet
11
Curved glass that refracts light
Down
2
Icy body with a tail near the sun
3
Form of thermal energy
5
Unit of force
6
Center of an atom or cell
7
Element found in all living things
12
Smallest unit of an element