Why do the areas in the frigid zone have six moths day followed by six months night

Because the earth is tilted towards the poles, so in summers the north pole will have continuous daylight for 6 months and south pole will have night for 6 months. Then in winters it will be reversed i. e. north pole will have night for the other 6 months and south pole will have continuous day light for 6 months. this proves that the poles experience day for 6 months and other 6 months they experience night.