On the other hand, if the teacher also tells the students that at present, there is no explanation as to how life came into existence, then the teacher is doing a perfect job.
By telling lies? How is that a "perfect job"? Are you sure you didn't mean to say "heckuva job?"
The truth is that there are many explanations for how life came into existence. We don't know which one is right. We do know that many of them are wrong. Saying that there are none at all would not be true.
Can there be any other way life could have come into existence?
Other way than what? Evolution is not a explanation for the origin of life.