Base your answers to questions 6 through 10 on the information and diagram below and on your knowledge
of biology.
The presence of air is believed to be important for root growth in bean plants. The apparatus available to
conduct an investigation is shown below. There are enough bottles and other materials to have multiple
setups. Air (for aeration) can be bubbled into the bottle through the rubber tube.
Rubber tube
from aerating
pump
Bean seedling
Plastic
modeling clay
Plant nutrient
solution
Source: Biology Handbook, SED 1960
Design an experiment to test the effect of aeration on the growth of roots of bean seedlings. In your answer,
be sure to:
6. State one reason why several different kinds of seedlings were not tested in this experiment.
7. State one reason why many setups should be used in both the experimental and control groups
8. Identify the dependent variable in the experiment.
9. Describe how the control group will be treated differently from the experimental group.