**Core Concept**
CO2 (carbon dioxide) is the preferred gas for laparoscopy due to its low solubility in blood, non-flammability, and minimal reabsorption by the body. CO2 is absorbed by the peritoneal cavity and exhaled by the lungs, eliminating the risk of gas embolism.

**Why the Correct Answer is Right**
CO2 is used in laparoscopy because it does not support combustion, reducing the risk of fire during the procedure. Additionally, CO2 is rapidly absorbed by the peritoneal cavity and exhaled by the lungs, minimizing the risk of gas embolism. The low solubility of CO2 in blood also reduces the risk of gas bubbles forming in the bloodstream.

**Why Each Wrong Option is Incorrect**
**Option A:** N2 (nitrogen) is not used in laparoscopy because it is not absorbed by the peritoneal cavity and can cause gas embolism. Nitrogen is also a diatomic gas that can cause tissue swelling.
**Option B:** O2 (oxygen) is not used in laparoscopy because it supports combustion, increasing the risk of fire during the procedure. Additionally, oxygen can cause tissue damage and promote oxidative stress.
**Option C:** N2O (nitrous oxide) is not used in laparoscopy because it is a potent anesthetic gas that can cause respiratory depression and other systemic effects.

**Clinical Pearl / High-Yield Fact**
CO2 is the preferred gas for laparoscopy because it is rapidly absorbed and exhaled by the body, minimizing the risk of gas embolism and other complications.

**Correct Answer: C. CO2. Carbon dioxide.**