Is it possible for students to suspend a teacher from school?

Nothing. The teachers are not employed and paid by the students. Teachers and other school staff are employed by the School Board, so only the School Board can suspend them. No worker in any job can be suspended from it by anyone but his employer. If students have an issue with a teacher, they must go to the school board and make their case with specific charges that fall under the guidelines for suspension of an employee

If all the pupils get together and then tell the head teacher(s) of a valid reason why they should be suspended then I don't see why not. They would probably suspend them until they investigate your claims. At my school we got a teacher fired because he was always showing up drunk - we started a petition and handed it to all his pupils and then took that to the head staff so maybe you could try that.

No. The reason they're called "teacher" is bc they know something you don't.