Bacaha isku dhafan ee bacaha ah ayaa aad ugu badan nolosheena waxayna noqdeen wax baakad muhiim ah sababtoo ah wax qabadkooda wanaagsan iyo isticmaalka ballaaran. Marka loo eego heerarka kala-soocidda ee kala duwan, bacaha bacaha isku dhafan waxaa loo qaybin karaa noocyo kala duwan.