DNA is important for inheritance because:
- It's fairly stable as a chemical, compared to something like RNA, which makes it good for storing genetic information over a long time
- It can be used to store information thru the arrangement of the bases (ATCG) and the genetic code
- The complementary base pairing rules (A-T, C-G) combined with the double-helix structure mean that a single strand can be used as a template to make a new strand, allowing genetic information to be passed to a daughter cell & between generations.
- It can be copied accurately, so information is not lost between generations.
As a side point... DNA is not a blueprint... the syllabus writers have NFI.