<h2>O sistema nervoso do corpo é formado pelo cérebro, pela medula espinhal, pela retina e por muitos outros nervos.</h2><h2> O sistema circulatório é constituído pelo coração, artérias, veias e capilares. </h2>
Answer:
Increasing your concentration of negative ions is a very important way to improve your health for a variety of reasons. They work to increase serotonin levels in your body, which improves mood and balances your mental health, helping combat depression and anxiety.
Explanation:
I've always been told that it's eight. This is only because the atom has to have the saem protons (positively charged) neutrons and electrons (negatively charged). However this does not occur with all atoms. :)
Sound waves are most effective when traveling through solids. Less effective when in liquids and least effective in air.
