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

To determine which of the options is only found associated with a child's bone, let's analyze each term: 1. **Diaphysis**: This is the shaft or central part of a long bone. It is present in both children's and adult bones. 2. **Marrow cavity**: This is the central cavity of bone shafts where marrow is stored. It is also present in both children's and adult bones. 3. **Epiphyseal plate**: This is a layer of cartilage found in the long bones of children and adolescents. It is responsible for the lengthening of bones during growth. In adults, this plate is replaced by the epiphyseal line after growth has ceased. 4. **Periosteum**: This is a dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints. It is present in both children's and adult bones. Based on this analysis, the **epiphyseal plate** is the only structure that is specifically associated with a child's bone, as it is involved in the growth process and is not present in adult bones. Thus, the answer is **Epiphyseal plate**.