nearly all fossils are found in sedimentary rock & if something is found in something else then that something else contains that something ->  sedimentary rocks can contain fossils  sedimentary rocks can contain fossils & metamorphic rocks do not contain fossils ->  sedimentary rocks can contain fossils and metamorphic rocks do not contain fossils  sedimentary is a class of rock & metamorphic is a class of rock ->  sedimentary and metamorphic are classes of rock  sedimentary and metamorphic are classes of rock & formation in the rock cycle means an old class of rocks changes into a new class of rocks ->  formation in the rock cycle can mean sedimentary rock changes into metamorphic rock  sedimentary rocks can contain fossils and metamorphic rocks do not contain fossils & formation in the rock cycle can mean sedimentary rock changes into metamorphic rock ->  in the rock cycle, sedimentary rocks that contain fossils can be changed into metamorphic rocks that do not contain fossils  in the rock cycle, sedimentary rocks that contain fossils can be changed into metamorphic rocks that do not contain fossils & if something that contains a thing is changed into something else that doesn't contain that thing, then that thing is lost / destroyed when that something changes into that something else ->  fossils are lost / destroyed when sedimentary rock changes to metamorphic rock  fossils are lost / destroyed when sedimentary rock changes to metamorphic rock & if fossils are destroyed in rock transition , then there will be gaps in the fossil record -> sedimentary rock changing to metamorphic rock causes gaps in the fossil record