Across
1
Unit of heredity
4
The Red Planet
5
Absolute temperature scale unit
6
Natural satellite of Earth
7
Icy body with a tail near the sun
11
Smallest unit of an element
Down
2
Nerve cell in the brain
3
Push or pull on an object
8
Gas essential for breathing
9
Ball of burning gas in space
10
Molten rock beneath Earth surface
12
Positive particle in nucleus