Across
1
Group of similar cells
2
The Red Planet
5
Gas essential for breathing
6
Unit of energy
8
Glass that splits light into spectrum
12
Precious yellow metallic element
13
Element found in all living things
14
Mass per unit volume
Down
2
Tissue that contracts for movement
3
Blocking of light by a celestial body
4
Form of thermal energy
7
Unit of electric potential
9
Magnetic metallic element
10
Center of an atom or cell
11
Path of a planet around the sun