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.