HSA 2007 Biology Item 26

A group of students conducted an experiment to study the growth of bean plants. They used two pots labeled “A” and “B.” Each pot contained 20 small bean plants of similar height. All the plants were treated alike except for the solution they received. Each day for five days, the plants in Pot A were given 40 milliliters of distilled water, while the plants in Pot B were given 40 milliliters of distilled water containing one gram of fertilizer. The table below shows the average height of the plants in each pot for each day of the experiment.

Which of these is being tested in this experiment?

1. the effectiveness of the water used on the plants
2. the effectiveness of the fertilizer used on the plants
3. the maximum height the plants will reach
4. the number of days the plants will grow