measures of brain activity during tasks requiring intelligence indicate that, in order to solve the same problem, the brains of people with high scores on standard intelligence measures

doesn't  have to work as hard as the brains of people with lower scores.

Explanation:

According to the neurobiological basis of human intelligence, some brains are more efficient than others, so one can argue that one person's brain could be more efficient than the brain of another person. Also, neuroimaging has shown that human intelligence is connected to  the structural and functional properties of the brain

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answer; the parasympathetic nervous system;