Across
1
Precious yellow metallic element
4
Tissue that contracts for movement
5
Tectonic landmass section
8
Gas essential for breathing
11
Form of thermal energy
12
Center of an atom or cell
Down
2
Substance with pH below 7
3
Unit of energy
6
Unit of heredity
7
Basic unit of life
9
Element found in all living things
10
Infectious microscopic agent