Across
1
Blocking of light by a celestial body
3
Tissue that contracts for movement
5
Molten rock beneath Earth surface
6
Unit of electric potential
7
Particle of light
10
Unit of energy
11
Curved glass that refracts light
Down
2
Fourth state of matter
3
The Red Planet
4
Gas essential for breathing
8
Precious yellow metallic element
9
Unit of force
12
Basic unit of life
13
Second lightest element