Describe enzyme structure.

In the above figure representing an enzyme catalysed reaction $\mathrm{a}$ and $\mathrm{b}$ respectively are;

Read the following statements:
(i) An active site of an enzyme is a crevice or pocket into which substrate fits.
(ii) Enzymes work efficiently at high temperature and high pressures, while inorganic catalysts get damaged at high temperatures.
(iii) Nucleic acids that behave like enzymes are called ribozymes.
(iv) Uncatalysed reactions proceed at rates vastly higher than that of catalysed ones.

Which of these statements are incorrect?

Which of the following factors affecting the enzyme activity is depicted in the given graph?

(i) Temperature

(ii) Substrate concentration

(iii) pH

(iv) Competitive inhibitor.