Across
1
Center of an atom or cell
4
Push or pull on an object
8
Group of similar cells
9
Icy body with a tail near the sun
11
Unit of heredity
12
Infectious microscopic agent
Down
2
Reddish electrical conductor
3
Tectonic landmass section
5
Nerve cell in the brain
6
Hottest planet in solar system
7
Chemical element in table salt
10
Curved glass that refracts light