What is the figure showing?

Observe the given fig. related to enzyme action and answer the following questions.
(i) What is the figure showing? (ii) Name the substances marked as (D) and ©.
(iii) What does the arrows marked © to (E) indicate?

(i) Figure is showing the activation energy requirement for non-catalysed and enzyme catalysed reactions.
(ii) Substances marked on arrows A and B are A Substrate. B End products.
(iii) Arrows marked shows.
C Energy of activaton without enzyme.
D Energy of activation with enzymes.
E Free energy difference between the substrate and the end product.