The first picture is for the first question and the second picture is for the 2nd question which is the topmost layer of the rock? layer a layer b layer c layer d which statement about the rock fossils is true? organism x existed for a short period of time. organism y became extinct before organism x. organism x and organism y existed at the same time. organism z became extinct much before organism x. scientists find an artifact next to an index fossil. what can they conclude about the unknown age of the artifact? the artifact is older than the index fossil. the artifact is younger than the index fossil. the artifact is approximately the same age as the index fossil. the artifact's age is not related to that of the index fossil. what process uses analysis of the decay of atomic particles to determine exact age? radioactive dating law of superposition relative dating geologic time