Across
1
Gas essential for breathing
4
Icy body with a tail near the sun
5
Hottest planet in solar system
6
Amplified beam of light
7
Magnetic metallic element
10
Smallest unit of an element
11
Path of a planet around the sun
12
Form of thermal energy
Down
2
Chemical element in table salt
3
Group of similar cells
4
Element found in all living things
5
Gas form of a liquid
8
Basic unit of life
9
Absolute temperature scale unit