Across
1
Basic unit of life
3
Path of a planet around the sun
5
Push or pull on an object
8
Positive particle in nucleus
9
The Red Planet
12
Form of thermal energy
Down
1
Icy body with a tail near the sun
2
Second lightest element
4
Element found in all living things
6
Magnetic metallic element
7
Chemical element in table salt
10
Center of an atom or cell
11
Unit of heredity