Someone please help me!!

How are the high islands of the pacific formed? a. by connected coral reefs called atolls b. by lagoons c. by moving glaciers d. by underwater volcanoes

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Sandstones that form in aeolian (wind/desert) environments appear very different from other sandstones, such as those formed in a beach/ shoreline environment and in rivers on land. give three identifying properties for each of the three sandstones that would tell a geologist which depositional environment they formed in. consider things such as the relationship between transportation and grain size, shape, roundness, sorting, fossils and composition.