21. Lungs
22. Ball and Socket
23. Synapses
24. When we move our body, "Nervous system" plays a very important role. It sends information to our body parts that how to move via motor neurons, and "Circulatory System" as it maintains our body pressure gradient with atmospheric pressure so we won't fall.
25. Flow of blood happens in two parts in our heart:
Right atrium --> Right ventricle --> Pulmonary Artery
& Left atrium --> Left ventricle --> Aorta
Now, blood flows to lungs from pulmonary artery and aorta where is gets oxidized.
Hope this helps!