Final answer:
The main difference between compact bone and spongy bone is in their structure. Compact bone is dense and strong, while spongy bone has an open network with spaces.
Step-by-step explanation:
The main difference between compact bone and spongy bone is in their structure. Compact bone is dense and strong, while spongy bone has an open network with spaces. Compact bone is found in the shaft and surface of bones, providing support and protection, while spongy bone is found in the ends of long bones and serves to give the bone strength.