Across
1
Path of a planet around the sun
4
Unit of force
5
Group of similar cells
6
The Red Planet
8
Reddish electrical conductor
12
Force that attracts objects together
Down
2
Second lightest element
3
Icy body with a tail near the sun
7
Mass per unit volume
9
Absolute temperature scale unit
10
Preserved remains of ancient life
11
Solid with repeating atomic pattern
13
Smallest unit of an element