Answer:
The primary purpose is to provide information to perform a task
It presents facts, principles, theories and reasoning related to a subject.
Step-by-step explanation:
We can only refer to something as being functional if it is serving its intended purpose. In a more literal interpretation, if something is working. Hence, a text can be referred to as being functional if it useful, that is it serves its main purpose of providing the required information necessary to perform a particular task. Furthermore, it should give additional information regarding the facts, principles, and reasoning behind a particular topic, problem or subject.