Which term refers to the growth of the brain and the use of mental skills?

The term that best describes the growth of the brain and the use of mental skills is "Intellectual development." This concept encompasses the progression of a person's cognitive functions over time, including the enhancement of critical thinking, problem-solving, reasoning, and understanding. Intellectual development specifically focuses on the changes and advancements in mental capabilities, which reflect how individuals acquire, process, and utilize knowledge throughout various stages of their life. The idea of intellectual development encompasses both the structural growth of the brain as well as functional improvements in mental skills.

While "cognitive abilities" also refer to mental skills and processes, it generally describes the specific capabilities, such as memory, attention, and reasoning, rather than the broader developmental aspect. "Intellectual growth" could be seen as a part of intellectual development, but it does not emphasize the overall progression and changes over time as explicitly. "Learning capacity" refers more to the potential one has to learn rather than the structured growth and evolution of intellectual abilities. In this context, intellectual development effectively captures both the growth of the brain and the application of those mental skills over time.