Question

some seats are kept for weaker sections of society so that they can get a share in political power.reason

Answer 1

This is because castes like sc, st, obc have been discriminated since ages. They were initially not allowed to use public wells, not allowed to enter temples, were forced to do unhygienic work. So the government of our nation decided to give them importance by reserving them positions in various departments even though they do not have enough potential. Politically they have reserved seats or constituencies in which only those can stand for elections and run government.
But now, it is being opposed by various Indian societies since it is unfair by giving more priority to those castes.