Across
1
Element found in all living things
3
Tissue that contracts for movement
6
Gas essential for breathing
7
Blocking of light by a celestial body
10
Unit of electric potential
Down
2
Substance with pH above 7
3
Molten rock beneath Earth surface
4
Unit of force
5
Curved glass that refracts light
8
Mass per unit volume
9
Hottest planet in solar system
11
Reddish electrical conductor
12
Nerve cell in the brain