Which of the following materials is known to release heat or energy?

Coal is a material known for its ability to release heat or energy through a process called combustion. When coal is burned, it undergoes a chemical reaction with oxygen, resulting in the release of energy in the form of heat. This heat can be harnessed for various applications, including generating electricity, cooking, or heating spaces.

The energy content in coal is significant, primarily due to its carbon-rich composition. The carbon atoms in coal combine with oxygen during combustion to produce carbon dioxide and heat, making it an effective fuel source for energy production.

In contrast, while wood, natural gas, and paper also release energy when burned, coal is particularly recognized for its high energy density and widespread use in industrial applications. Thus, among the listed options, coal stands out as a prominent energy-releasing material.