Answer: Endoplasmic reticulum
Explanation:
Endoplasmic reticulum is a continuous membrane system which is is a series of flattened sacs in the cytoplasm of the eukaryotic cells.
It serves in synthesis and folding, modification and the transportation of the proteins molecules.
The xylem and phloem of the plants also helps in transportation of the materials from one place to other parts of the body.