Body functions refer to the various processes that keep an organism alive and healthy. These include essential activities such as digestion, respiration, and circulation. Each function relies on specific structures within the body, such as organs and systems, to perform its role effectively. Body structures are the physical components that make up an organism. This includes cells, tissues, organs, and organ systems. For example, the heart is an organ that pumps blood, while the lungs facilitate gas exchange. Together, these structures work in harmony to support the body's functions.