Across
1
Our home planet
3
Unit of electric potential
5
Icy body with a tail near the sun
6
Center of an atom or cell
7
Basic unit of life
8
Infectious microscopic agent
9
Path of a planet around the sun
10
Unit of force
11
Ball of burning gas in space
Down
2
Amplified beam of light
3
Gas form of a liquid
4
Second lightest element
5
Reddish electrical conductor
6
Nerve cell in the brain