Enzymes are destroyed at:

Which enzyme is associated with oxidation and reduction reactions in a cell?

As temperature changes from $3^o \,C$ to $45^o \,C$,the rate of enzyme activity will

Which enzymes are responsible for changing the arrangement of atoms in substrate molecules?

What are the different classes of enzymes? Explain any two with the type of reactions they catalyse.

The given graphical representation relates to enzyme activity under three conditions ($pH$,temperature,and substrate concentration). What do the given axes $X$ and $Y$ represent?
$X$-axis $-$ $Y$-axis