7-dehydrocholesterol (sometimes known as provitamin D3) is a chemical that, in the presence of ultraviolet light, is converted by the body to previtamin D3 which is then isomerized into Vitamin D3.
... Contents
Urethra
In anatomy, the urethra is a tube that connects the urinary bladder to the outside of the body. The urethra has an excretory function in both ...