Across
1
Force that attracts objects together
3
Center of an atom or cell
8
Mass per unit volume
11
Naturally occurring inorganic solid
Down
1
Unit of heredity
2
Ball of burning gas in space
4
Form of thermal energy
5
Biological catalyst
6
Smallest unit of an element
7
Basic unit of life
9
Tectonic landmass section
10
Our home planet