What is the control of blood pressure levels when the blood pressure levels are too low? what is the control of blood pressure levels when the blood pressure levels are too high? what are the body structures involved? , answer all the questions.

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?