Quick Answer. The function of the cartilaginous rings of the trachea is to stabilize the trachea and keep it rigid while allowing the trachea to expand and lengthen when the person breathes. If the trachea was not supported in this way, it would simply collapse because of the pressure of the chest.
1 The Pill. The pill is the common name for oral contraception. It's one of the safest, most effective, and popular methods of birth control. The pill is made up of synthetic forms of hormones that naturally occur in a female's body - progestin and estrogen.
(Newser) â The practice of sterilization as a family-planning method is facing scrutiny after 13 women died following such procedures in India. But female sterilization is actually the most common form of birth control, with some 223 million women undergoing the procedure in 2009, NPR reports.