OpenStax
Open Stax: Anatomy & Physiology: Skeletal System Functions
This site helps you understand the human skeletal system, a body system composed of bones and cartilage that performs critical functions for the human body.
National Cancer Institute at the National Institutes of Health
Seer Training Modules: Introduction to the Skeletal System
Self-guided learning activity where students learn about the structure and function of the human skeletal system. There is a short quiz at the end of the lesson to check for understanding.