This question portrays what occurs during DNA replication in which nucleotide sequences that are complementary to the template strand are synthesized. The DNA molecule consists of two long polynucleotide chains composed of four nucleotide subunits held together by hydrogen bonds. Each of the chain is known as a DNA strand.
In the DNA, base portions are paired together in an hydrogen bonding using the complementary base pairing rule. Complementary base pairing is the phenomenon where DNA Guanine always binds to Cytosine in an hydrogen bonding while Adenine binds to Thymine in the same manner i.e. A-T, G-C. The complementary base pairing that binds nucleotide bases in DNA is responsible for the double-helical structure of the DNA.
Hence, in a DNA molecule with nucleotide sequence CCTAGCT, a complementary strand of DNA will have the nucleotide sequence GGATCGA.
