I’ll mark as BRANLIEST!!
30 POINTS!!
Please help me!!

Answer:
They are complimentary DNA strands of each other
I remember them via AT (AT-AT from Star Wars and this gets you 2 H bonds) and CG (cross guard light saber, the ridiculous one with the helm of the sword having it's own light saber so it is crossed and has 3 H bonds). Ridiculous makes things more memorable imo.
Explanation: