Across
1
Element found in all living things
2
Blocking of light by a celestial body
4
Force that attracts objects together
5
Disturbance that transfers energy
6
Form of thermal energy
11
Substance with pH above 7
12
Path of a planet around the sun
Down
2
Biological catalyst
3
Naturally occurring inorganic solid
7
Group of similar cells
8
Substance with pH below 7
9
Amplified beam of light
10
Curved glass that refracts light