1. Some scientists investigated the effect of two antibiotics (methicillin and penicillin) on the growth of two different bacteria.

They used filter paper discs soaked in antibiotic solution and placed the discs on two agar plates, one had been spread with bacteria A and the other with bacteria B.

The filter paper discs were prepared as follows:

1. Control

2. Penicillin

3. Methicillin

Figure 1 shows the results from the investigation:

Figure 1

(i) Suggest what the paper disc might have been soaked in for the control.

(1)

(ii) Describe and explain the results in Figure 1.

(4)