A student investigated the time taken for the complete digestion of starch by amylase found in the saliva of 25 individuals of a species of mammal.

A sample of saliva was collected from each individual and mixed with 5 cm³ of starch suspension. Samples of the mixture were tested for the presence of starch.

The student recorded the time taken for the complete digestion of starch.

The investigation was repeated with the same individuals on the following day.

The results of the student’s investigation are shown in the table.

a. Plot a graph to display these data.

b. Describe the patterns in the results.

c. Suggest a reason for the differences between the results for day 1 and day 2.

d. Suggest how you might control the variables in this investigation to compare a different species of mammal with the mammal studied.

Transcribed Image Text:

Time taken for complete Number of individuals day 1 digestion of starch / min day 2 35 2 8 40 6 10 45 9 4 50 2 55 3 1