How are roots stems and leaves connected?

As with all living things, plants are made up of cells. In plants, the cells are rigid, containing a cell wall. Where cell walls aren't present in animal cells, the cell wall in plant cells keeps the plant rigid, as well as connecting the different parts of the plant together. In various other less evolved plants, including ferns, are interconnected to from their leaves, roots, and stems by a vascular system of tubes.