What does random access rely on?

• A. Using fixed storage blocks.
• B. Using unique address sequences and PCR primer sets.
• C. Using longer homopolymers.
• D. Using higher GC content.

Answer: (B)

Random access in DNA data storage relies on addressing data blocks so you can pick out a single item from a large pool. Each block carries a unique address sequence, acting like a barcode that identifies its content. A carefully designed set of PCR primers matches that address, so you can selectively bind and amplify only the target block. This selective amplification lets you retrieve one specific file without sequencing or decoding everything else in the pool. Other options don’t provide that selective targeting: fixed storage blocks don’t enable easy pick-out of one item from many, longer homopolymers don’t address individual blocks, and higher GC content affects stability rather than enabling selective access.