2. What is the difference between functional and non-functional?

A functional requirement describes what a software system should do, while non-functional requirements place constraints on how the system will do so.

Let me elaborate.

An example of a functional requirement would be:

A system must send an email whenever a certain condition is met (e. g. an order is placed, a customer signs up, etc).

A related non-functional requirement for the system may be:

Emails should be sent with a latency of no greater than 12 hours from such an activity.

The functional requirement is describing the behavior of the system as it relates to the system's functionality. The non-functional requirement elaborates a performance characteristic of the system. (stack overflow)

Answer: function means that its able top mobilize or operate as of which non-functional means that its not able to mobilize or can not operate