Enerji, or energy, is the ability to do work or cause change. It exists in various forms, including kinetic energy, potential energy, thermal energy, and chemical energy. Energy can be transformed from one form to another, such as when electricity powers a light bulb, converting electrical energy into light and heat. Energy is essential for all living organisms and is used in countless processes, from photosynthesis in plants to metabolism in animals. It is measured in units like joules or calories. Understanding energy is crucial for addressing issues like climate change and developing sustainable practices.