How are matter and nutrients cycled back into the ecosystem from which they came?

Which statement best describes the role of religion and culture in ancient medicine?

Which of the following can occur to two segments of a population if they are geographically isolated 1.) they can only share some types of genes 2.)both groups most likely become extinct 3.)they find a way to come back together 4.)eventually they become separate species

How many electrons can occupy any electron orbital?