Final answer:
The structural feature of DNA that suggests the mechanism for its replication is complementary base pairing, as it allows each strand to serve as a template for creating an exact copy of the genetic information.
Step-by-step explanation:
The structural feature of DNA hinting at the mechanism for its replication is B. complementary base pairing. The double helix model of DNA suggests that each of the two strands serves as a template for the new strand, thanks to the precise pairing of nitrogenous bases (A pairs with T and C pairs with G) enabled by hydrogen bonding. This base pairing ensures that the genetic information is accurately copied during DNA replication. Complementary base pairing is crucial because it means that each base on one strand dictates which base will be added to the new strand, ensuring that genetic information is preserved with each new copy of DNA.
In contrast to other choices offered such as antiparallel strands, constant diameter, and double helix, it is the complementary base pairing that most directly suggests how the DNA molecule could generate an exact duplicate of itself. The other features are important aspects of DNA’s structure but do not themselves hint at the mechanism of replication.