Describe the essential parts of a simple chemical cell and explain why both electrodes and electrolyte are needed.

A simple chemical cell contains two different metal electrodes in contact with an electrolyte. The different metals react differently, and the electrolyte allows ions to move so a potential difference can be produced.

This answer identifies the two required physical parts: different metal electrodes and an electrolyte. The metals must be different because their different reactivities create a voltage. The electrolyte is needed because ion movement completes the circuit inside the cell.