Across
1
The Red Planet
3
Biological catalyst
4
Unit of electric potential
5
Ball of burning gas in space
8
Force that attracts objects together
9
Fourth state of matter
10
Unit of force
Down
1
Measure of matter in an object
2
Center of an atom or cell
6
Push or pull on an object
7
Blocking of light by a celestial body
11
Disturbance that transfers energy