A student carried out the Benedict's test on four different concentrations of glucose solution and then recorded the time taken for the first appearance of a colour change (the end-point). The student found it difficult to identify the first appearance of a colour change and consistently timed each solution for two seconds after the colour change first appeared. This introduced a source of error into the experiment. Which statements about this error are correct? 1 The effect of the error will be reduced if the student performs three repeats at each concentration of glucose. 2 The error will prevent the student from identifying which solution has the highest concentration of glucose. 3 The error is systematic as the student consistently timed each solution for two seconds after the end-point.