A square day mark with an odd number functions similarly to which type of buoy?

A square daymark with an odd number functions similarly to a green buoy because both serve as navigational aids that indicate the presence of channels or points of interest for boaters. Green buoys generally are used on the left side of the channel when entering from the sea and indicate safe water areas, while square daymarks with odd numbers also denote these same safe navigation points.

The use of specific colors and shapes in navigation aids is integral to the uniformity of the navigation system, aiding mariners in identifying their surroundings and making informed decisions. In this context, the odd-numbered square daymark would signal to boaters that they are approaching an area that requires particular attention, aligning it with the function of a green buoy.