Answer:
hydrogen bonding
Explanation:
The two strands of DNA are held together by hydrogen bonds between complimentary nucleotides.
I'm gonna assume you mean copper
Copper<span> is a chemical element with symbol Cu (from Latin: cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure </span>copper<span> has a reddish-orange color.</span>
This is false
А
Because they are compounds, they cannot be pure substances.
Because:Compounds are pure substance
