Across
1
Infectious microscopic agent
2
Icy body with a tail near the sun
4
Unit of heredity
6
Unit of force
7
Nerve cell in the brain
Down
2
Element found in all living things
3
Measure of matter in an object
5
Positive particle in nucleus
8
Group of similar cells
9
Curved glass that refracts light
10
Particle of light