Hope has given comfort to many people(find line of this meaning)
Answers
Answer:
An atoll ( /ˈætɒl, ˈætɔːl, ˈætoʊl, əˈtɒl, əˈtɔːl, əˈtoʊl/),[1][2] sometimes known as a coral atoll, is a ring-shaped coral reef, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim.[3] (p60)[4]

Satellite picture of the Atafu atoll in Tokelau in the Pacific Ocean
The typical atoll was originally formed as an oceanic volcano. A coral reef grew around the shore of the volcano and then, over several million years, the volcano went extinct and eroded and subsided completely beneath the surface of the ocean. The reef and the small coral islets on top of it are all that is left of the original island, and a lagoon has taken the place of the former volcano. For the atoll to persist, the coral reef must be maintained at the sea surface, with coral growth matching any relative change in sea level (subsidence of the island or rising oceans)