hope this helps
I do think that they close to not allow too much of either water or air from entering.
the hollow tube allows water to flow easily.
https://www.bbc.co.uk/bitesize/guides/z28g7p3/revision/1
Ball and Socket Joint
This type of joint allows for a wide range of rotation and movement. The shoulder and hip are ball and socket joints.
Answer:
Arginine - Leucine - Proline - Asparagine - Lysine - Arginine
Explanation:
