Which of the following is only found associated with a child's bone? Diaphysis Marrow cavity Epiphyseal plate

The epiphyseal plate is a region of growth found in children's long bones that allows for lengthening as they grow. This cartilage layer gradually ossifies and is replaced by bone as the child matures, ultimately leading to the cessation of bone growth when they reach adulthood. In contrast, the diaphysis and marrow cavity are structures present in all long bones, regardless of age. So while the diaphysis and marrow cavity are also found in adult bones, the epiphyseal plate is uniquely associated with developing bones in children.