Across
1
Tissue that contracts for movement
4
Our home planet
5
Unit of electric potential
8
Force that attracts objects together
10
Substance with pH above 7
11
Magnetic metallic element
12
Nerve cell in the brain
Down
2
Mass per unit volume
3
Gas essential for breathing
6
Smallest unit of an element
7
Naturally occurring inorganic solid
9
Unit of heredity