Parasitism is a type of symbiotic relationship where one organism, called the parasite, benefits at the expense of another organism, known as the host. The parasite relies on the host for nutrients and survival, often harming the host in the process. Common examples of parasites include tapeworms, fleas, and lice. In parasitism, the host may experience various negative effects, such as illness or weakened health. While some parasites can be specific to one host species, others may infect multiple species. This relationship is an important aspect of ecosystems, influencing population dynamics and species interactions.