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

1. A. Nitric oxide
2. B. Nitrous oxide
3. C. Nitrogen dioxide
4. D. Nitrogen pentoxide

Answer: A

Explanation

Nitric oxide (NO) is a crucial signaling molecule produced naturally by the human body. It acts as a potent vasodilator, meaning it relaxes the smooth muscles in the walls of blood vessels, causing them to widen. This widening, or dilation, of blood vessels leads to increased blood flow and a reduction in blood pressure. The other options, Nitrous oxide (N2O), Nitrogen dioxide (NO2), and Nitrogen pentoxide (N2O5), are different chemical compounds with distinct properties and are not primarily involved in this physiological process in the human body. This question tests basic biological and chemical knowledge relevant to human health, a common area in the Science & Technology syllabus.