Across
1
The Red Planet
4
Gas essential for breathing
5
Magnetic metallic element
7
Positive particle in nucleus
10
Tissue that contracts for movement
12
Naturally occurring inorganic solid
Down
2
Smallest unit of an element
3
Chemical element in table salt
6
Blocking of light by a celestial body
8
Ball of burning gas in space
9
Nerve cell in the brain
11
Center of an atom or cell