Across
1
Measure of matter in an object
3
Path of a planet around the sun
6
Basic unit of life
7
Hottest planet in solar system
9
Glass that splits light into spectrum
10
Unit of heredity
12
Tissue that contracts for movement
Down
2
Force that attracts objects together
4
Natural satellite of Earth
5
Center of an atom or cell
8
Preserved remains of ancient life
11
Absolute temperature scale unit