A drug entering the body through the oral route is first __________ in the __________ and goes through the liver in something called __________ metabolism.

The correct choice highlights the process by which a drug is absorbed in the intestine after being administered orally and subsequently undergoes "first pass" metabolism in the liver.

When a drug is taken orally, it dissolves in the gastrointestinal tract, primarily in the intestines, where it is absorbed into the bloodstream. This absorption process is significant because a large portion of the drug not only enters the bloodstream but is also subjected to metabolism by the liver before it can exert its pharmacological effects.

The term "first pass metabolism" refers to the phenomenon where the drug is metabolized at a specific site in the body (the liver) before reaching systemic circulation. This can affect the bioavailability of the drug, meaning that the amount of active drug that reaches the site of action is reduced due to this metabolic process.

Understanding this concept is critical in pharmacology, as it helps explain variations in drug effectiveness and dosing requirements for oral medications.