It is important for a food business to keep out flying insects. screens on kitchen doors can be very effevtive as long as the screen mesh is the right size, there are no tears and

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?