Intelligence refers to certain mental powers. There is no general agreement on which mental powers are intelligent or part of intelligence. The idea comes from a Latin word: "intelligo" meaning to "choose between different options". A part of intelligence allows people to solve problems. These problems may be easy to solve. They may also be difficult to solve, and involve abstract thought. For some, intelligence is a property, or characteristic of the mind. For others, it is simply the working of the brain, especially the cerebral cortex.