A Critical Section is a part of a computer program where shared resources, such as variables or data structures, are accessed. When multiple processes or threads try to access these resources simultaneously, it can lead to inconsistent or incorrect results. To prevent this, only one process or thread is allowed to execute the critical section at a time, ensuring data integrity. To manage access to the critical section, various synchronization mechanisms are used, such as mutexes, semaphores, or locks. These tools help coordinate the execution of processes, allowing them to wait their turn and access shared resources safely without causing conflicts or data corruption.