GEOLOGY

Detailed explanation-1: -Almost all fossils are preserved in sedimentary rock. Organisms that live in topographically low places (such as lakes or ocean basins) have the best chance of being preserved. This is because they are already in locations where sediment is likely to bury them and shelter them from scavengers and decay.

Detailed explanation-2: -The oldest-known sedimentary rocks on the Earth comprise the 3.8-billion-year-old Isua Sequence of southwestern Greenland. The rocks were once sediments formed by chemical precipitation from ocean water. Intermittent eruptions from nearby volcanoes added other sediment layers.

Detailed explanation-3: -The law of superposition states that rock strata (layers) farthest from the ground surface are the oldest (formed first) and rock strata (layers) closest to the ground surface are the youngest (formed most recently). A fossil is the remains or traces of plants and animals that lived long ago.

Detailed explanation-4: -Inclusions are always older than the rock they are found in. Even if we did not see the igneous and metamorphic rocks in surface exposures, the fact that they occur in the (brownish) sediment unit indicates the presence of older ingneous and metamoprhic rocks that supply material to that unit.