Answer:
Carbohydrate
Step-by-step explanation:
Fiber is made from an indigestible carbohydrate that comes from plants (unlike, for example, pasta and breads, which are basically carbohydrates that are digestible to us). It is indigestible to humans because we do not have the enzymes necessary to absorb it, so it passes completely through the digestive system.
An example of a non-digestible carbohydrate for humans is cellulose, to digest it we would have to have an enzyme called cellulase.