A polymer is a large molecule made up of repeating structural units called monomers, which are connected by chemical bonds. These molecules can be natural, like proteins and cellulose, or synthetic, such as plastic and nylon. Polymers have diverse properties and uses, making them essential in various industries, including packaging, textiles, and medicine. The unique characteristics of polymers, such as flexibility, strength, and resistance to chemicals, depend on their composition and structure. For example, rubber is a polymer known for its elasticity, while polyethylene is a common plastic used in bags and containers. Understanding polymers helps in developing new materials and technologies.