Across
1
The Red Planet
2
Preserved remains of ancient life
4
Blocking of light by a celestial body
6
Tissue that contracts for movement
11
Gas essential for breathing
Down
2
Push or pull on an object
3
Icy body with a tail near the sun
5
Basic unit of life
7
Absolute temperature scale unit
8
Mass per unit volume
9
Tectonic landmass section
10
Substance with pH above 7