Final answer:
A safe water mark may be vertically striped, spherical, or showing a white light. These marks are used to guide mariners and indicate safe areas for navigation in water bodies.
Step-by-step explanation:
A safe water mark may be all of the above - vertically striped, spherical, and showing a white light. Safe water marks are used to guide mariners and indicate safe areas for navigation. They come in various forms, including striped buoys, spherical buoys, and buoys with white lights. These marks help ships avoid hazards and navigate safely in water bodies.