Because the kidney is the one who produce the urine , a urine is a fluid that contains of ion , water and small soluble compounds. narrow muscular tubes in between the kidneys and bladder is called the ureters. the kidney has the renal cortex, real medulla, the renal pyramids and actually a lot more.
The Diaphragm needs to be fitted by a doctor.
If it's credible it usually will cite where it got it's information to avoid copyright bs
Because this is who we are and it is just the way of life that you are born and developed in the body were in