Science Homework Help

I need help with a Anatomy question. All explanations and answers will be used to help me learn.

https://www.youtube.com/embed/Iz0Q9nTZCw4https://www.youtube.com/embed/Iz0Q9nTZCw4

https://www.youtube.com/embed/OTgpN62ou24

https://www.youtube.com/embed/m-v5G8C70pc

https://www.youtube.com/embed/Fly-tntiG54

https://www.youtube.com/embed/YO244P1e9QM

https://www.youtube.com/embed/URUJD5NEXC8
https://www.youtube.com/embed/_POdWsii7AI

https://www.youtube.com/embed/N6IAzlugWw0