Final answer:
All portable circular saws must have a guard for safety purposes, protecting users from the exposed blade during operation and when not in use.
Step-by-step explanation:
All portable circular saws must be equipped with a guard. This safety feature is essential to protect users from the moving blade, especially in the event of a kickback, which can lead to serious injuries. The guard covers the blade when the saw is not in use and retracts when the saw is being used, allowing for safe operation while still providing easy access to the cutting surface.
It's vital for students and workers using these tools to be aware of the proper safety protocols and to always ensure their equipment is properly maintained and equipped with functioning safety features.