Across
1
Force that attracts objects together
2
Tectonic landmass section
6
Natural satellite of Earth
7
Curved glass that refracts light
8
Ball of burning gas in space
9
Center of an atom or cell
11
Compound containing oxygen
Down
2
Particle of light
3
Magnetic metallic element
4
Disturbance that transfers energy
5
Basic unit of life
6
Naturally occurring inorganic solid
10
Element found in all living things