Fifteen-month-old Lorraine and 5-year-old Joaquin are siblings. Which of the following statements about their physical growth is true? Both Lorraine and Joaquin are undergoing steady physical growth. Joaquin's physical growth is rapid, while Lorraine's growth is steady. Both Lorraine and Joaquin are undergoing rapid physical growth. Lorraine's physical growth is rapid, while Joaquin's growth is steady.