Which of the following features may pose a hazard to navigation?

All of the mentioned features—coral reefs, wrecks, and shoals—can significantly impact safe navigation and pose hazards to vessels.

Coral reefs, for instance, are typically found in shallow waters and can be dangerous to ships, especially larger vessels that may not have the maneuverability to avoid them. They can damage the hulls of vessels if there is an unexpected encounter, making them an important feature to note on nautical charts.

Wrecks are another notable hazard. These may be remnants of sunken ships that can be situated in navigable waterways or anchorage areas. Wrecks can create obstructions and potential dangers to navigation, often requiring mariners to alter their course to safely maneuver around them.

Shoals are formations that rise up from the seabed and can also present navigation risks. They are often submerged during normal tidal conditions but can become dangerously exposed at low tides. Depending on their location, they can lead to grounding incidents if ships are not properly aware of their positions relative to these shallow areas.

Therefore, recognizing that all these features can pose distinct navigational challenges underscores the importance of hydrographic surveying in ensuring safe maritime travel.