How are the aromatic rings represented? Why?
Aromaticity is indicated by a circle inside the ring. The circle indicates that all the bonds are equivalent.
The most common aromatic compound is benzene.
Benzene is a resonance hybrid of two contributors.
It doesn't consist of alternating double and single bonds.
Rather, every bond is a 1½ bond.
These partial bonds are indicated by dashed lines.
For simplicity, the dashed lines are usually drawn as a dashed or a solid circle.