I believe the answer is X chromosome and Y chromosome.
The cell membrane is selectively permeable, allowing only certain substances to pass through. Passive transport is a way that small molecules or ions move across the cell membrane without input of energy by the cell. The three main kinds of passive transport are diffusion, osmosis, and facilitated diffusion.
Chemicals that help chemical reactions occur at faster rates in living organisms are known as Enzymes.
Cliffs don't form in wet climates because they will become mud and eventually fall, causing a mudslide.
The patient can be subjected to intraoperative cholangiography wherein a stent in the bile duct will be placed and a radiopaque dye will be injected. X-rays will be taken. This is to locate the level of obstruction and to confirm if there is a common bile duct obstruction. In extracting stones, the surgeon can prefer doing an endoscopic retrograde cholangiopancreatography or ERCP and perform basket extraction of the common bile duct stone; or to surgically remove the sphincter of Oddi to allow easy passage of the stones.