Nitric oxide was discovered as a secondary messenger in the 1980s and has grown in popularity since that time. In fact, it was named molecule of the year in 1992 by Science Magazine, one of the leading global scientific publications, and the Nobel Prize in Physiology and Medicine for 1998 was awarded to the scientists who discovered its properties as a signaling molecule. Add to that the link to Viagra, one of the most profitable sexual enhancement drugs on the market, and you have a molecular superstar.

The main function of viagra is to relax the muscles of the blood vessels in some areas of the body. It is used for the treatment of erectile dysfunction and for high blood pressure. The component of viagra is a competitor to the enzyme PDE5, breaking down cGMP. In the penis, blood is trapped, which results in the erection being maintained. When cGMP levels decrease, the concentration of calcium ions increases, causing smooth muscle contraction.

Explanation:

the answer to your question is sperm

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.