Mental activities refer to the cognitive processes that take place in the mind, such as thinking, perceiving, problem-solving, and decision-making. These activities involve various mental operations and can vary in complexity.
Cognition refers to the overall process of acquiring knowledge through mental activities like perception, attention, memory, language, and problem-solving.
Memory is the ability to store and retrieve information acquired through past experiences or learning. It involves encoding, storage, and retrieval processes.