Across
1
Positive particle in nucleus
3
Basic unit of life
6
Hottest planet in solar system
7
Path of a planet around the sun
8
Smallest unit of an element
9
The Red Planet
11
Natural satellite of Earth
Down
2
Center of an atom or cell
4
Gas form of a liquid
5
Chemical element in table salt
10
Element found in all living things
12
Group of similar cells