At approximately what age does the center of mass reach the naval?

• A. Five
• B. Nine
• C. Eight
• D. Eleven

Answer: (C)

The movement of a child’s center of mass as they grow is the key idea here. Early in life the body is relatively top‑heavy—the head and trunk carry more mass—so the center of mass sits high in the torso. As a child grows, their legs lengthen and body proportions shift, pulling the center of mass downward toward the abdomen and, by around eight years old, to roughly the level of the navel. This timing is a common approximation used in teaching because it reflects a noticeable shift toward a more adult-like balance posture, which helps with stability and control in movement. Five is generally earlier than this shift, while nine and eleven tend to reflect a further downward position that occurs later in childhood.