What limits do skeleton have as historical sources

Skeletons remain which are considered most important to recreate the historical picture sometimes could produce many obstacles for historians. It is very difficult to find the skeleton intact as it get degenerated with time as they were exposed to harsh weather conditions and prone to scavenging. Sometimes historians have to study with just a bone of human skeleton which limits its information in historical context.

a. theta waves. this is because the person is in a light sleep which means the brain waves would show these kind of waves.