A polymer is a large molecule composed of repeating structural units called monomers, connected by covalent bonds. Polymers can be natural, such as proteins and nucleic acids, or synthetic, like plastic and nylon. Their properties, such as strength, flexibility, and thermal stability, depend on the type of monomers used and their arrangement. Polymers are ubiquitous in everyday life and have diverse applications in areas like medicine, manufacturing, and technology, significantly impacting various industries.