Across
1
Form of thermal energy
3
Fourth state of matter
5
Tissue that contracts for movement
7
Substance with pH below 7
9
Path of a planet around the sun
11
Curved glass that refracts light
12
Tectonic landmass section
Down
1
Second lightest element
2
Ball of burning gas in space
4
Basic unit of life
6
Naturally occurring inorganic solid
8
Group of similar cells
9
Gas essential for breathing
10
Push or pull on an object