Answer:
Due difference in cultural beliefs.
Step-by-step explanation:
The choice of co-sleeping or independent sleeping is a good example of a custom complex, and the underlying cultural beliefs because in some of the culture, co-sleeping is considered as a bad habit and prohibited by the culture but encourages independent sleeping while on the other hand, some culture allows the co-sleeping due to no prohibition in their cultural believes so we can say that custom complex is responsible for this choice of sleeping.