Across
1
Biological catalyst
5
Center of an atom or cell
6
Substance with pH below 7
7
Path of a planet around the sun
8
Ball of burning gas in space
9
Molten rock beneath Earth surface
Down
2
Magnetic metallic element
3
Measure of matter in an object
4
Force that attracts objects together
10
Solid with repeating atomic pattern
11
Push or pull on an object
12
Absolute temperature scale unit