Across
1
Ball of burning gas in space
4
Push or pull on an object
5
Unit of electric potential
7
Gas essential for breathing
11
Gas form of a liquid
12
Basic unit of life
Down
2
Our home planet
3
Reddish electrical conductor
6
Nerve cell in the brain
7
Compound containing oxygen
8
Smallest unit of an element
9
Unit of heredity
10
Substance with pH above 7