<span>7 electrons in each outer shell
Group 17
Most reactive
Fluorine, Chlorine, Bromine, Iodine, Astatine
Alkali Metals:
1 electron is each outer shell
Group 1
Also reactive, but not as much as the halogens
Lithium, Sodium, Potassium, Rubidium, Cesium, Francium </span>
Answer:
The suprachiasmatic nuclei enable the nervous system to respond to daily light/dark alterations through their stimulation of melatonin.
Explanation:
Melatonin is a hormone produced naturally by the body. Its function is to regulate the body's circadian cycle. This hormone is stimulated and begins to act by changing between a light environment and a dark environment. This stimulation interacts with the suprachiasmatic nuclei making the nervous system understand this change and luminosity of the environment and respond to the action of melatonin.
I think it is from the Paleozoic era
Hope this helps
Myocardium, that's because myocardium simply means 'muscular tissue of the heart'. It is not pericardium or connective tissue as these are only small, specific areas of the heart and a heart attack can cause cells to die anywhere in the heart.
