Answer:
7 in girls and age 10 in boys
Step-by-step explanation:
Around the ages of 7 in girls and age 10 in boys, the volume of gray matter in the caudate, a part of the basal ganglia involved in control of movement and muscle tone, peaks. This is one of the reasons as to why girls are more athletic and flexible earlier when compared to boys who develop more muscle tone later on in life.