Explain why two siblings except identical twins have the exactly the same alleles

having exactly the same DNA sequences, twins start accumulating genetic variation from the earliest stages of development, researchers at Iceland-based company deCODE genetics found, meaning that one twin harbors variants that aren't present in the other.

the main thing i would use is bricks because if there is a hurricane, there is a great possibility for the house to still stand. and i would also use plexiglass windows instead of regular windows because plexiglass isn't prone to breaking.