Which of the following is used to keep debris out of the intake system on a watercraft?

The intake grate is designed specifically for the purpose of keeping debris out of the intake system on a watercraft. It is typically placed at the front or bottom of the watercraft where water is drawn in for propulsion. By preventing larger objects, such as weeds, rocks, and other debris, from entering the intake, the grate helps ensure the engine operates efficiently and reduces the risk of damage. This function is crucial for the longevity and performance of the watercraft, as blocked intakes can lead to overheating and mechanical issues.

The other components, while essential for the operation of the watercraft, do not serve the same function. The drive shaft transmits power from the engine to the propeller, facilitating propulsion. The propeller itself is responsible for pushing the water to create forward motion but does not have a role in filtering debris. The exhaust port is involved in expelling exhaust gases from the engine, which is important for performance but unrelated to protecting the intake system. Thus, the correct answer is indeed the intake grate, as it directly addresses the need to keep debris out of the watercraft's intake system.