DNA is ______ stranded.

• A. Double stranded
• B. Single stranded
• C. Triple stranded
• D. Quadruple stranded

Answer: (A)

DNA's structure is double-stranded. In cells, DNA consists of two long polynucleotide chains that form a right-handed double helix and run in opposite directions (antiparallel). The bases on one strand pair with the bases on the other strand—adenine with thymine and guanine with cytosine—creating complementary strands. This pairing makes the strands interchangeable templates, which is essential for accurate replication and gene expression. The double-stranded arrangement also protects the genetic material and adds stability. While single-stranded DNA can occur temporarily during replication or in some viral forms, the typical, stable form in most organisms is double-stranded; triplex or quadruplex structures are not the standard configuration.