What are the differences between a root and a rhizome?

[Ahmed Abdullah]

Mosses and ferns have rhizome whereas a mango tree has root.
Rhizomes are used for absorbing water and nutrient from ground by mosses as higher plants use their roots. SO I don't understand why two distinct terms are used for things of similliar functions.

[jim mcnamara]

A rhizome is modified stem tissue, roots are, well, roots. Their tissues are different from stems.

Have you had any plant anatomy? Once you have studied the tissues (like xylem, phloem, pericyle, etc.) it will make more sense.

Plus, tracheophytes like mosses have relatively undifferentiated tissues, compared with flowering plants. It's kinda like comparing roundworms and humans - humans have many more tissues.