'It's called' is a contraction of 'it is called', which is passive voice. The subject is being called by someone else. This is often used to give the name of someone or something. 'It called' means the subject is doing the calling, whether literally or figuratively. That's active voice.
Furthermore, what is the difference between call and called?
As verbs the difference between calling and call is that calling is (call) while call is to request, summon, or beckon.
Beside above, why is it or why it is?
“Why” would be a noun used as the subject. “Is” stands as your linking verb. “It” is a pronoun used as a predicate nominative referring back to the subject. “It” would usually be followed by an adjective clause or phrase, modifying (and explaining) it.
What is the calling?
Definition of calling. 1 : a strong inner impulse toward a particular course of action especially when accompanied by conviction of divine influence. 2 : the vocation or profession in which one customarily engages.
Which is why grammar?
In that is why, that is a demonstrative pronoun. In which is why, which is a relative pronoun. That in that is why is usually the subject of a sentence or a clause that can stand alone: I want to be involved in town government, and that is why I'm running for mayor.