Answer:

Introduction:
The question asks about a concept that enables work to be done. There are four options given, namely energy, the Sun, heat, and sound. The correct answer is energy. In this response, we will explain why energy is the correct answer and provide a detailed explanation.

Explanation:
Definition of Energy:
Energy is the capacity to do work. It is a fundamental concept in physics and is defined as the ability to cause change or perform work on an object. Energy can exist in various forms and can be transferred or converted from one form to another.

Forms of Energy:
There are many forms of energy, some of which include:

1. Kinetic Energy: This is the energy possessed by an object due to its motion. For example, a moving car has kinetic energy.

2. Potential Energy: This is the energy possessed by an object due to its position or state. It can be gravitational potential energy, elastic potential energy, or chemical potential energy, among others.

3. Thermal Energy: This is the energy associated with the motion of particles within a substance. It is commonly referred to as heat energy.

4. Electrical Energy: This is the energy associated with the flow of electric charges. It is commonly used to power electrical devices and systems.

5. Chemical Energy: This is the energy stored in the bonds of chemical compounds. It is released during chemical reactions such as burning or metabolism.

6. Light Energy: This is the energy carried by electromagnetic waves, including visible light. It is responsible for our ability to see and is used in various applications such as lighting and solar power.

Why Energy Enables Work to be Done:
Energy is necessary for work to be done because work is defined as the transfer of energy from one object or system to another. When work is done on an object, energy is transferred to it, causing a change in its state or motion.

For example:

- When a person pushes a box, they are doing work on the box by transferring their energy to it. This causes the box to move.

- When a light bulb is turned on, electrical energy is converted into light energy, allowing us to see.

- When a battery-powered toy is turned on, chemical energy stored in the battery is converted into electrical energy, which powers the toy's movement.

In all these examples, energy is essential for work to be done. Without energy, no work can be performed.

Conclusion:
In conclusion, energy is the concept that enables work to be done. It exists in various forms such as kinetic, potential, thermal, electrical, chemical, and light energy. Without energy, work cannot be performed, and the world as we know it would not be able to function.