Q. Which one of the following is synthesised in human body that dilate blood vessels and increases blood flow?

Answer: (a) Nitric oxide

Nitric Oxide (NO): Nitric oxide is a molecule synthesized in the human body that plays a crucial role in various physiological processes, including the dilation of blood vessels (vasodilation) and increasing blood flow.
- It is produced by endothelial cells lining the blood vessels and works by relaxing the smooth muscles in the vessel walls, leading to dilation and improved blood circulation.

Nitrous Oxide (N2O): Nitrous oxide, also known as laughing gas, is an anesthetic and analgesic used in medical settings.
- It’s a colorless, non-flammable gas with a slightly sweet scent and taste.
- In addition to its recreational use, nitrous oxide is also used in various medical and industrial applications, including as an anesthetic and an engine performance enhancer.
Nitrogen Dioxide (NO2): Nitrogen dioxide (NO2) is a reddish-brown, toxic gas that is a major air pollutant.
- It’s primarily produced by burning fuels like coal, oil, and gas.
- NO2 contributes to the formation of ozone and other harmful pollutants, negatively impacting human health and the environment.
Nitrogen Pentoxide (N2O5): Dinitrogen pentoxide, also known as nitrogen pentoxide or nitric anhydride, is a chemical compound with the formula N2O5. It’s a colorless solid that sublimes slightly above room temperature and is a potent oxidizer.
- The uses of dinitrogen pentoxide are-
  - It is used as a robust oxidizer in high-fuel rockets.
  - It is used to ease nitration in non-water based solvents.
  - It is used for making explosives.
  - It is used to denote the light intensities transmitted when the cell was occupied by the decomposing nitrogen pentoxide and when occupied by the completely decomposed nitrogen pentoxide.