Across
1
Compound containing oxygen
5
Biological catalyst
6
Measure of matter in an object
7
Group of similar cells
8
Tissue that contracts for movement
11
Element found in all living things
13
Curved glass that refracts light
Down
2
Chemical element in table salt
3
Second lightest element
4
Blocking of light by a celestial body
9
Unit of energy
10
Substance with pH above 7
12
Magnetic metallic element