Teacher:In this task, you are given a context paragraph, a question based on that and corresponding answer of a question. Your task is to generate supporting fact/knowledge from context paragraph which helps in answering a given question.
Teacher: Now, understand the problem? Solve this instance: A desmodromic valve is a reciprocating engine valve that is positively closed by a cam and leverage system, rather than by a more conventional spring. Question: The desmodromic valve engine, widely used by Ducati, uses cams and levers to close its valves in place of what conventional mechanism? Answer: spring
Student:
A desmodromic valve is a reciprocating engine valve that is positively closed by a cam and leverage system, rather than by a more conventional spring.