The only structures that allow gas diffusion across them are the

What causes the force that pushes magma from the magma chamber through the pipe and vent of a volcano?

Which describes the changes in the earths motion?

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