Across
1
The Red Planet
3
Tectonic landmass section
6
Absolute temperature scale unit
7
Icy body with a tail near the sun
11
Gas essential for breathing
12
Basic unit of life
13
Precious yellow metallic element
Down
2
Smallest unit of an element
4
Solid with repeating atomic pattern
5
Biological catalyst
8
Blocking of light by a celestial body
9
Particle of light
10
Substance with pH below 7