Across
1
Element found in all living things
4
Basic unit of life
5
Blocking of light by a celestial body
6
Force that attracts objects together
7
Smallest unit of an element
9
Naturally occurring inorganic solid
Down
2
Tissue that contracts for movement
3
Mass per unit volume
4
Reddish electrical conductor
8
Particle of light
10
Disturbance that transfers energy
11
Molten rock beneath Earth surface
12
Unit of force