A reaction carried out in an inert solvent S proceeds by the sequence of elementary steps below.
Step 1: A+B→C+D
Step 2: C+E→F
Step 3: F+B→G+C
Step 4: G→A
Classify each of the species A, B, C, D, E, F, and G as a reactant, product, intermediate, or catalyst for the overall reaction. (The solvent S does not participate.)