Across
1
Reddish electrical conductor
4
Gas essential for breathing
5
Basic unit of life
6
Group of similar cells
8
Second lightest element
12
Preserved remains of ancient life
Down
1
Solid with repeating atomic pattern
2
Force that attracts objects together
3
Glass that splits light into spectrum
7
Tissue that contracts for movement
9
The Red Planet
10
Unit of heredity
11
Substance with pH below 7