Some living things are made of a single cell, they are called organism

Why do carbohydrate molecules function so well as fuel for the body?

What happens when the cell copies its chromosomes

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?