Explain why the damage to the cells lining the ileum reduces absorption of the products of digestion and why this reduces absorption of water.

Not all patients in hospital with C. difficile develop diarrhoea.

Scientists measured the anti-toxin antibody concentration in hospital patients with and without C. difficile infection.

They measured the anti-toxin antibody concentration four times:

• on admission to hospital (day 0) • on day 3 • on day 6 • on the day the patient left the hospital.

Figure 4 shows the scientists' results.

The scientists suggest that the anti-toxin antibody could be given to some patients as a form of passive immunity.

Use Figure 4 to suggest how this passive immunity would work and which patients should be offered this anti-toxin antibody.

To be used as passive immunity treatment, the anti-toxin antibody would be injected. If it was given by mouth, it would be digested.

Describe how the anti-toxin antibody would be digested.