Across
1
Force that attracts objects together
3
Center of an atom or cell
7
Unit of force
8
Basic unit of life
9
Blocking of light by a celestial body
Down
1
Unit of heredity
2
Ball of burning gas in space
4
Naturally occurring inorganic solid
5
Element found in all living things
6
Unit of energy
10
Nerve cell in the brain
11
Substance with pH below 7
12
Mass per unit volume