An element with a valence of 8 are most likely noble gases (He, Ne, Ar, etc) which means they're already stable so they dont need to undergo chemical bonds with another atom because they already have a full valence shell.
It depends on what illness and what country you are in but Mayo Clinic and Johns Hopkins are good sources.
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<em><u>Alexander Graham Bell</u></em></h3><h2>
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Alexander Graham Bell is often credited as the inventor of the telephone since he was awarded the first successful patent.
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A molecule called DNA (deoxyribonucleic acid) is passed from adult organisms to their offspring during reproduction. This molecule containsthe instructions for an organism to develop, grow, survive and reproduce.