Across
1
Element found in all living things
4
Force that attracts objects together
5
Icy body with a tail near the sun
6
Preserved remains of ancient life
8
Blocking of light by a celestial body
11
Unit of heredity
Down
2
Absolute temperature scale unit
3
Measure of matter in an object
7
Curved glass that refracts light
9
Unit of energy
10
Mass per unit volume
12
Tectonic landmass section
13
Fourth state of matter