Across
1
Chemical element in table salt
3
Element found in all living things
5
Center of an atom or cell
7
Reddish electrical conductor
10
Our home planet
11
The Red Planet
Down
2
Smallest unit of an element
4
Tissue that contracts for movement
6
Amplified beam of light
8
Magnetic metallic element
9
Ball of burning gas in space
12
Group of similar cells
13
Blocking of light by a celestial body