Across
1
Preserved remains of ancient life
4
Unit of heredity
5
Icy body with a tail near the sun
6
Absolute temperature scale unit
7
Unit of force
8
Force that attracts objects together
9
Amplified beam of light
13
Unit of energy
Down
2
Gas essential for breathing
3
Blocking of light by a celestial body
5
Basic unit of life
10
Gas form of a liquid
11
Glass that splits light into spectrum
12
Biological catalyst