Across
1
Substance with pH below 7
3
Particle of light
4
Biological catalyst
7
Mass per unit volume
8
Natural satellite of Earth
9
Our home planet
Down
2
Icy body with a tail near the sun
3
Positive particle in nucleus
5
Element found in all living things
6
Precious yellow metallic element
10
Disturbance that transfers energy
11
Hottest planet in solar system