B if not please comment back .
Answer:
In a primary cell, two electrodes (one of copper and other of zinc) of metal atoms are used. These electrodes are dipped in an electrolyte solution that causes the metals to produce their respective positive and negative ions.
In this way, the flow of charges takes place and supply the electricity to the source.
Unlike a primary cell, a dry cell contains paste of an electrolyte instead of the solution. The contents of electrolyte paste react with each other through a chemical process and convert the chemical energy into electrical energy.
Could u put it in english u can use goggle translation if u do not know how to
The answer is pressure and gravity
Health and safety are two reasons