Across
1
Basic unit of life
3
Our home planet
4
Second lightest element
6
Nerve cell in the brain
12
Mass per unit volume
13
Hottest planet in solar system
Down
2
Tissue that contracts for movement
5
Unit of energy
7
Biological catalyst
8
Naturally occurring inorganic solid
9
Amplified beam of light
10
Chemical element in table salt
11
Form of thermal energy