Final answer:
An Isolated Danger Mark signifies a maritime hazard such as a submerged object. It has a distinct pattern of black and red stripes with two black spheres on top and emits two flashes every ten seconds for visibility.
Step-by-step explanation:
The term Isolated Danger Mark refers to a type of navigation mark used in maritime contexts to indicate the presence of a danger such as a submerged rock, shipwreck, or similar isolated hazard in the ocean that has safe water around it. The marking is typically indicated by a black-and-red-striped buoy or beacon with two black spheres placed one above the other as top marks, and it is often accompanied by a specific light pattern. In this case, the mentioned Lights: Fl (2) 10s means the light's characteristic is two flashes every ten seconds. These marks help in providing critical information that ensures the safety of maritime navigation.