Across
1
Reddish electrical conductor
4
Chemical element in table salt
5
Unit of power
6
Mass per unit volume
7
Basic unit of life
8
Molten rock beneath Earth surface
9
Substance with pH above 7
12
Unit of energy
Down
2
Center of an atom or cell
3
Path of a planet around the sun
4
Ball of burning gas in space
10
Unit of heredity
11
Biological catalyst