Across
1
Biological catalyst
2
Element found in all living things
3
Smallest unit of an element
6
Path of a planet around the sun
8
Absolute temperature scale unit
9
Disturbance that transfers energy
11
Measure of matter in an object
Down
2
Icy body with a tail near the sun
4
Reddish electrical conductor
5
Amplified beam of light
7
Second lightest element
10
Substance with pH below 7
12
Ball of burning gas in space
13
Our home planet