Across
1
Ball of burning gas in space
3
Center of an atom or cell
4
Path of a planet around the sun
5
Smallest unit of an element
6
Gas form of a liquid
Down
2
Positive particle in nucleus
3
Nerve cell in the brain
5
Substance with pH below 7
Ball of burning gas in space
Center of an atom or cell
Path of a planet around the sun
Smallest unit of an element
Gas form of a liquid
Positive particle in nucleus
Nerve cell in the brain
Substance with pH below 7