1. On what condition we are justified to use the method for this experiment and estimate the Composition of the mixture and the binding constant K. 2. Why should we select the optimal wavelength, why we should reset the zero point from each experiment, and how? 3. Why we should reset the zero poim from each sample. 4. Why should we use the buffer solution? Should not the volume of the buffer solution reduce to half for the second set of the sample? 5. What do you think the aspects in the experiment that can induce experimental errors?