Across
1
Infectious microscopic agent
4
Disturbance that transfers energy
5
Naturally occurring inorganic solid
6
Center of an atom or cell
11
Mass per unit volume
12
Magnetic metallic element
13
Compound containing oxygen
Down
2
Blocking of light by a celestial body
3
Curved glass that refracts light
7
Chemical element in table salt
8
Nerve cell in the brain
9
Substance with pH above 7
10
Basic unit of life