Answer:
It looks like ladder.
Step-by-step explanation:
It is similar to ladder in shape but it is curly/winding at some points after a specific distance. Like it is not straight like a ladder but it is turned at a specific distance.
Complementary mean it is has Arginine attached to Thymine, Guanine attached to Cytosine etc.
These basis are attached to one another in this complementary fashion.