<https://www.brainintraining.org/courses/locomotor-system-bundle-2/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.brainintraining.org/courses/locomotor-system-bundle-2/lessons/intro-to-cell-bio-water-and-aqueous-environment-of-cell-copy-2/>