Residue, or remnant, refers to the leftover material that remains after a process has occurred. This can be seen in various contexts, such as cooking, where food scraps are left after a meal, or in chemistry, where substances remain after a reaction. Residue can also refer to the remnants of a physical object, like the leftover pieces of a broken item. In environmental science, residue often pertains to pollutants or waste that linger in ecosystems after industrial activities. For example, pesticides can leave harmful residues in soil and water, affecting plants and animals. Understanding residue is crucial for managing waste and minimizing environmental impact.