Across
1
Magnetic metallic element
4
Second lightest element
5
Our home planet
6
Form of thermal energy
8
Absolute temperature scale unit
12
Naturally occurring inorganic solid
13
Biological catalyst
Down
2
Unit of heredity
3
Blocking of light by a celestial body
7
Mass per unit volume
9
Unit of electric potential
10
Natural satellite of Earth
11
Nerve cell in the brain