1.1. A group of scientists investigated the rates of absorption of different sugars using two pieces of the intestine.

One piece of the intestine was poisoned with cyanide which stops cellular respiration.

The results are shown in the table below.

Which of the sugars in the table are absorbed by active transport?

1.2. Explain why you chose these sugars, using evidence from the table in part (a).

1.3. One of the scientists states ‘All four of the sugars we investigated can be absorbed by diffusion.

Is this statement correct or incorrect? Justify your answer.

1.4. One of the sugars absorbed by active transport is glucose.

Xylose is a sugar that is the same size as glucose, but it is not absorbed by active transport.

Suggest a reason why.