I need help:) please

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

Can a trait be both polygenic and have multiple alleles? explain why or why not.

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