An atoll is a reef or island indicative of an undersea volcano. a. true b. false

Hello!

The statement "An atoll is a reef or island indicative of an undersea volcano is True.

An atoll is a ring-shaped coralline oceanic island or a set of small islands from a coral reef that forms an internal lagoon. When there is a volcanic island, the Coral reef grows around it and the old volcano slowly sinks into the ocean, when the right conditions are met. The most famous atolls are the Bikini, Maldives, and Midway atolls. 

Have a nice day!

If you will look at the sun through magnifying glass then the glass will defocus your eyes and so damage will be reduced.

The investiture controversy began as a power struggle between pope gregory vii (1072–85) and henry iv, holy roman emperor (1056–1106).[2] a brief but significant struggle over investiture also occurred between henry i of england and pope paschal ii in the years 1103 to 1107, and the issue played a minor role in the struggles between church and state in france, as well.by undercutting the imperial power established by the salian emperors, the controversy led to nearly 50 years of civil war in germany, and the triumph of the great dukes and abbots. imperial power was finally re-established under the hohenstaufen dynasty. historian norman cantor: