Explanation:
An electric cell is a device that converts chemical energy into electrical energy. It consists of two electrodes (a positive electrode called the cathode and a negative electrode called the anode) and an electrolyte solution. The central terminal of an electric cell is always positive.

Reason:
The positive terminal of an electric cell is connected to the cathode, which is the electrode where reduction (gain of electrons) takes place during the chemical reaction. The cathode is usually made of a material that readily accepts electrons, such as copper or silver. When the chemical reaction occurs, positive ions from the electrolyte are attracted to the cathode, where they gain electrons to form neutral atoms or molecules.

Function:
The positive terminal of an electric cell is responsible for delivering the electrical energy produced by the cell to an external circuit. When a load (such as a light bulb or a motor) is connected to the positive and negative terminals of the cell, the flow of electrons (current) is established, and the electrical energy is used to power the load.

Importance:
Identifying the positive terminal of an electric cell is crucial when connecting it to an external circuit. If the cell is connected in reverse, with the positive terminal connected to the negative terminal of the load, the cell may not work properly or may not deliver any electrical energy. Therefore, it is important to correctly identify the positive terminal to ensure the proper functioning of the electric cell.

Conclusion:
The central terminal of an electric cell is always positive because it is connected to the cathode, where reduction occurs during the chemical reaction. Understanding the polarity of an electric cell is essential for its proper use in various electronic devices and circuits.