Whats the question?
I mean yes it was an advancement .
Answer:
the Vocoder, SIGSALY, CDs, MP3 music files
Explanation:
Tetravalent
We have already seen an example of how a covalent bond can form between two hydrogen atoms producing molecular (H2) as opposed to the atomic form of hydrogen. ... As in all its compounds and its elemental forms, carbon is tetravalent, which means that it always forms four bonds.
