Final answer:
The retractable lower blade guards are a common safety feature of a circular saw, providing protection against accidental contact with the blade.
Step-by-step explanation:
One common safety feature of a circular saw is the retractable lower blade guards. These guards are designed to cover the lower portion of the saw blade when it is not in use, preventing accidental contact and reducing the risk of injuries. They can be easily pulled back when the saw is in operation.
Learn more about safety feature of a circular saw