A bottle.I has a neck and but a head
The answer to this question would be: isotonic
An isotonic solution has a same tonicity/concentration to the cell. This kind of solution will not cause osmosis to occur so it wouldn't shrink or swell the cells. This is why an isotonic solution is safer for the cells. The normal saline solution is isotonic to human cells and used frequently in medicine to replace body fluid.
When the reactant is single compound before the reaction and become more than single compound after reaction is called decomposition reaction
Probably life science or biology.
