Across
1
Element found in all living things
3
Precious yellow metallic element
4
Positive particle in nucleus
6
Group of similar cells
9
The Red Planet
10
Blocking of light by a celestial body
Down
2
Path of a planet around the sun
3
Unit of heredity
5
Force that attracts objects together
7
Amplified beam of light
8
Nerve cell in the brain