Answer:
Histamine is a protein produced by <u>mast cells</u> in the body. It plays a very important role in the immune system of the body. Histamine is released in the body when <u>affected by an allergen</u>, e.g, pollen or animal dander. The immune system of the body will respond to such allergen by <u>making more mucus in the nose by releasing histamine</u>. There will be sneezing, itching, coughing and runny nose in response. This is a <u>basic defense of the body's immune system</u> to not enter any particle inside the body.
It changes because when the 2 tectonic plates collide they form mountains and volcanoes.
Continental drift causes tectonic plates to either "pull apart" or "crash" into each other.
Plates that crash into each other either form mountains, or when one slides under the other (a subduction zone) volcanoes from.
Answer:
All isotopes of an element have the same number of protons and electrons, which means they exhibit the same chemistry. The isotopes of an element differ only in their atomic mass, which is given by the mass number (A), the sum of the numbers of protons and neutrons.
Explanation:
Hope this <em><u>Helped!</u></em> :D
Valence.
The electrons in the outer shell of an atom are called valence electrons.
Valence electrons determine whether the an element is ready form compounds. These electrons can be gained, lost, or shared in the formation of compounds.
