Across
1
Particle of light
4
Nerve cell in the brain
5
Group of similar cells
7
Unit of power
9
Disturbance that transfers energy
12
Substance with pH above 7
13
Curved glass that refracts light
Down
1
Tectonic landmass section
2
Gas essential for breathing
3
Smallest unit of an element
6
Tissue that contracts for movement
8
Blocking of light by a celestial body
10
Mass per unit volume
11
Solid with repeating atomic pattern
14
Molten rock beneath Earth surface