give two features of DNA that is important for DNA replication

complementary base pairing - new strand can be synthesised based on the base sequence on the template strand, so that the resulting strand synthesised is identical to the coding strand.
hydrogen bonds between complementary base pairs can be broken by DNA helicase to separate the strands during replication. hydrogen bonds also form between complementary bases on the template strand and free activated nucleotides. (2 hydrogen bonds between A and T, 3 between C and G. this therefore affects which bases are able to pair together.)