Across
1
Natural satellite of Earth
2
Blocking of light by a celestial body
3
Tissue that contracts for movement
7
Element found in all living things
9
Unit of force
10
Measure of matter in an object
12
Unit of energy
Down
2
Biological catalyst
4
Precious yellow metallic element
5
Second lightest element
6
The Red Planet
8
Center of an atom or cell
11
Path of a planet around the sun