Prerequisites are the necessary conditions or requirements that must be met before starting a particular course, program, or activity. They ensure that individuals have the foundational knowledge or skills needed to succeed. For example, a mathematics course may require students to have completed algebra before enrolling. In various fields, prerequisites can include specific educational qualifications, prior experience, or even certain certifications. These requirements help maintain a standard of learning and ensure that participants are adequately prepared. For instance, a medical program may require applicants to have a background in biology and chemistry.