students should always question what they are taught instead of accepting it passively

Questions act as bridge between students and learning. As students are learners so more questions would result in higher learning and expanding their knowledge.
Historically, questions are base of knowledge, as Greek philosophers started questioning the universe the knowledge started expanding. it is human nature to ask question when he wants to understand anything as child starts asking questions as soon as he begins talking. Similarly the beginning of science is attributed to invention of wheel and begining of physics is the question asked by Newton when an apple fell on the ground. So students should be encouraged to ask questions as the questioning would help them to explore the unexplored areas of the field and expand the horizons of learning.