Across
1
Unit of electric potential
4
Path of a planet around the sun
5
Mass per unit volume
6
Disturbance that transfers energy
10
Chemical element in table salt
12
Gas essential for breathing
13
Our home planet
Down
2
Icy body with a tail near the sun
3
Unit of force
7
Infectious microscopic agent
8
Gas form of a liquid
9
Unit of power
11
Group of similar cells