All animals depend on plants. Some animals eat plants for food. Other animals eat animals that eat the plants. Each plant or animal has different structures which serve different functions in growth, survival, and reproduction. For example, humans have distinct structures of the body for walking, holding, seeing, and talking.
Different substances can damage the body and how it functions.
Students should understand that some substances such as prescription drugs can be beneficial but that any substance can be harmful. All animals depend on plants. Some animals eat plants for food. Other animals eat animals that eat the plants. An organism's patterns of behavior are related to the nature of that organism's environment, including the kinds and numbers of other organisms present, the availability of food and resources, and the physical characteristics of the environment.