Question

how to identify which circuit is in sereis and parralel

Answer 1

if circuit connect in series so that when one bulb is damaged or fused so all bulb are getting fused or danaged
and if circuit is connect in parralel than one bulb is fused then all bulbs are bright not fused so in this way we and identify

Answer 2

Series: If the current moving through the wire remains undivided it is in series  Parallel : If the current passing through the wires divides to different junctions it is in parallel