Across
1
Unit of energy
4
Positive particle in nucleus
5
Nerve cell in the brain
8
Substance with pH above 7
9
Chemical element in table salt
10
Second lightest element
13
Preserved remains of ancient life
14
Unit of heredity
Down
2
Path of a planet around the sun
3
Hottest planet in solar system
6
Amplified beam of light
7
Gas essential for breathing
11
Push or pull on an object
12
Tissue that contracts for movement