<em>Answer is B. The fossils in the lower layers are older than the fossils in the upper layers.</em>
Characteristics shared by members of a group may include interests, values, representations, ethnic or social background, and kinship ties. (Sorry this is late) just saw this now.
These molecules need to pass through specific proteins or transmembrane proteins embedded in the cell membrane. A specific type of an integral membrane protein.
x or y because both can cause it
