Macroinvertebrates are small animals without a backbone that can be seen with the naked eye. They include organisms such as insects, crustaceans, and mollusks. These creatures are commonly found in aquatic environments like rivers, lakes, and ponds, where they play essential roles in the ecosystem. These animals are important for several reasons. They help break down organic matter, serve as food for larger animals like fish and birds, and can indicate the health of an ecosystem. Scientists often study macroinvertebrates to assess water quality and monitor environmental changes.