Which of the following root words is associated with the term "fiber"?

The root word associated with "fiber" is indeed fibr/o. This root is derived from the Latin word "fibra," which directly translates to "fiber." In medical terminology, the prefix or root "fibr/o" is commonly used to refer to fibrous tissues or structures. It is frequently seen in terms related to connective tissues and disorders affecting fibers, such as fibrosis or fibroblast. Understanding this root word is essential in the context of medical terminology, as it connects to various conditions and tissues involving fibrous structures.

The other root words serve different meanings: sarc/o refers to flesh, my/o pertains to muscle, and por/o is related to pores or openings. Therefore, fibr/o is the precise root word that signifies "fiber."