Which process changes igneous rock into metamorphic rock?

What do scientists need to look at before developing an argument

What best explains the inability for life to exist in earth early atmosphere

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?