A DNA molecule consists of two polynucleotide strands that form a double helix. The strands are held together by hydrogen bonds between the nitrogen‑containing bases. One strand is complementary to the other strand, which means that a base on one strand is paired with a base on the opposite strand. The nucleotide bases in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). Choose the DNA sequence complementary to GACT (A) AGTC (B) GACT (C) TCAG (D) CTGA

Answer: D) CTGA

Explanation:

As the question says, DNA consists of two complementary strands held together by hydrogen bonds between bases.

Nucleotides are the monomers of DNA, which means they are the basic building block of it. The nucleotides consists of:

A sugar: deoxyribose A phosphate. A base: Adenine (A), Thymine (T), Guanine and Cytosine (C)

Adenine pairs with Thymine, they form two hydrogen bonds between them. While Cytosine pairs with Guanine, they form three hydrogen bonds between them. This is because each base can bond with a specific base in a process called complementary base pairing.

So, the complementary sequence of GACT is CTGA.