Across
1
Preserved remains of ancient life
4
Icy body with a tail near the sun
5
Absolute temperature scale unit
6
Unit of energy
Down
2
Center of an atom or cell
3
Second lightest element
7
Gas essential for breathing
8
Group of similar cells
Preserved remains of ancient life
Icy body with a tail near the sun
Absolute temperature scale unit
Unit of energy
Center of an atom or cell
Second lightest element
Gas essential for breathing
Group of similar cells