Across
1
Path of a planet around the sun
3
Substance with pH above 7
4
Element found in all living things
5
Second lightest element
10
Unit of heredity
11
Absolute temperature scale unit
Down
2
Blocking of light by a celestial body
6
Reddish electrical conductor
7
Glass that splits light into spectrum
8
Naturally occurring inorganic solid
9
Nerve cell in the brain