The figure given below shows the conversion of a substrate into product by an enzyme. In which one of the four options $(1-4)$  the components of reaction labelled as $\mathrm{A},\mathrm{B},\mathrm{C}$ and $\mathrm{D}$ are identified correctly?

The curve given below shows enzymatic activity with relation to three conditions (pH, temperature and substrate concentration)

What do the axis x and y represent?

Which of the following describes the given graph correctly?

Which of the following sets of monosaccharides forms sucrose?