Which of the following warns of dangers such as rocks and shoals?

The correct answer is diamonds, which are used in navigational signage to indicate specific hazards or dangers in the water. When you see a diamond shape, it typically warns boaters about potential dangers, such as rocks, shoals, and other underwater hazards that could pose risks to navigation. Understanding these symbols is critical for ensuring safe boating practices, as they help mariners identify areas that require extra caution.

Other shapes, such as circles and squares, serve different purposes in the navigation system. Circles are often used for regulatory purposes, while squares may indicate information or instructions not directly related to dangers. Crossed diamonds specifically designate areas that are not safe to enter, indicating a prohibition rather than a warning about hazards like rocks or shoals. This distinction is important for safe navigation on Michigan's waterways, as recognizing these signs can prevent accidents and enhance overall safety.