What do you mean by foreign bodies?

Foreign bodies refer to objects or substances that are not naturally present in a particular environment or organism. In a medical context, they can be items like splinters, metal fragments, or swallowed objects that enter the body and may cause injury or infection. In other fields, such as environmental science, foreign bodies can refer to pollutants or invasive species disrupting local ecosystems. Essentially, they are any external items that interfere with the normal function or health of a system.