Final answer:
Defects on a school bus must be addressed and fixed before the bus is operated again to ensure safety for student passengers.
Step-by-step explanation:
Any defect found on a school bus must be fixed before the vehicle is operated as a school bus again. This is because school buses are used to transport children and therefore must adhere to the highest safety standards to ensure the well-being of the passengers. If a defect is discovered, it's essential to address the issue immediately to maintain a safe transportation environment for the students.