Across
1
Measure of matter in an object
2
Basic unit of life
3
Our home planet
6
Hottest planet in solar system
11
Precious yellow metallic element
Down
2
Icy body with a tail near the sun
4
Ball of burning gas in space
5
Unit of energy
7
Substance with pH above 7
8
Preserved remains of ancient life
9
Smallest unit of an element
10
Reddish electrical conductor
12
Mass per unit volume