I think it's b because it seems obvious
Answer:
The onion cell has a cell wall, unlike the human skin cell.
Explanation:
Only plant cells have cell walls.
Enzymes bind with chemical reactants called substrates. There may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. In some reactions, a single-reactant substrate is broken down into multiple products. ... The enzyme's active site binds to the substrate.