Question

anatomy and physiology help please

Answer 1

http://prntscr.com/nbkg38

Answer 2

@Shadow @Ultrilliam @finny @Narad

Answer 3

I think their question is worded weirdly...a catalyst is being used in B but obviously a substrate is being used in both...Because catalysts lower the activation energy in a chemical reaction

Answer 4

But if i had to choose, it looks like maybe an inhibitor is being used in reaction A because you can see that the line doesn't reach the "end" mark. Inhibitors stop reactions from happening or slows them down