Across
1
Force that attracts objects together
4
Substance with pH below 7
6
Center of an atom or cell
9
Tectonic landmass section
10
Curved glass that refracts light
Down
1
Precious yellow metallic element
2
Substance with pH above 7
3
Magnetic metallic element
5
Our home planet
7
Biological catalyst
8
The Red Planet