Phosphorus atom require to form 3 single covalent bond to have a complete octet in its valence shell. Phosphorus has a electron configuration 2.8.5 hence require to gain three electrons to acquire the octet electron configuration that is an electron configuration of 2.8.8.
Answer:
D. Hydrogen bonds between complementary base pairs89
Explanation:
A DNA molecule is composed of two long polynucleotide chains made of four types of nucleotide subunits, two purines (adenine and guanine) and two pyrimidines (cytosine and thymine). These nucleotides are joined by covalent bonds forming a phosphate-sugar backbone. <em>These strands are held to one another with hydrogen bonds between the base portions of complementary nucleotides.</em>
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