After a hypothesis has been repeatedly tested and becomes widely accepted, it is considered a?

fact.

law.

theory.

principle.

What is histamine and what is its role in allergic reactions

Hemoglobin is the compound in red blood cells that carries oxygen to the body. the distribution of hemoglobin in women in g/dl of blood is approximately normally distributed with mean 14 and standard deviation 1. too little hemoglobin, and you're anemic. 2. too much, and (unless you live at high altitudes), you can have other problems.

Which kingdom includes some organisms that have no nucleus and can live in an environment with an extremely high salt content