Question

which is better series combination or parallel combination in electric and why

Answer 1

Parallel connection is better because the voltage across each appliance connected in parallel is same that means if a number of bulbs are connected in parallel then irrespective of the number no bulb will get dim, but in series as the number of bulbs increase the resistance increase voltage decrease so the bulb gets dim.
Also the appliances connected in parallel work independently of each other.
The total resistance in a parallel connection is quite low.

Answer 2

parallel combination , because by following ways:-
1).all the electrical appliances have its own switch due to which it can turn on or off separately.
2).in this circuit, same voltage is supplied to each electrical appliances.
3). in parallel combination ,if one electrical appliances stops working then all other appliances keep working