Base your answer on the information and diagram below and on your knowledge of biology To study how bacteria respond to antibiotics, four paper discs, three treated with different antibiotics and one treated with water, were placed on a nutrient
source with bacteria and left for 24 hours. The water and the antibiotics on the discs diffused into the nutrient source. If the antibiotic stopped the bacteria
from growing, a circular area of no bacterial growth around the discs could be seen
Discs with
different antibiotics
Nutrient source
with bacteria
No bacterial
growth
24 Hours
Disc with
water
Bacterial
growth
In this experiment, the purpose of using a disc treated with water is that it
O serves as the conclusion for the experiment
is needed to provide additional moisture
O serves as a control for the experiment
O is needed as a standard safety procedure