Across
1
Icy body with a tail near the sun
3
Particle of light
5
The Red Planet
6
Element found in all living things
9
Infectious microscopic agent
10
Force that attracts objects together
Down
2
Blocking of light by a celestial body
3
Tectonic landmass section
4
Tissue that contracts for movement
7
Path of a planet around the sun
8
Smallest unit of an element
11
Nerve cell in the brain