?

ACT® Science

Free Version

Upgrade subject to access all content

Difficult

Repeat Experiment

ACTSCI-1GXFR4

A rival researcher believes that the auxin IG3 will be more effective in developing roots than the giberellins were. She obtains five bean plants and treats each one with a different IG3 solution. She then measures the length of the main root every 3 days. Her results are summarized in the table below:

$$ \text{ Length of Main Root (cm):} $$

Plant # Conc. of IG$_3$ (ug/ml) Day 3 Day 6 Day 9 Day 12 Day 15
1 20 2 2.2 2.5 2.8 3.1
2 40 2 2.4 2.6 2.9 3.1
3 60 2 2.1 1.7 1.4 .7
4 80 1. 1.2 .9 0 0
5 100 1.5 .8 .5 0 0

A Scientist decides to test the effect the addition of giberellic acid has on root growth in newly planted pea shoots. She sets up an experiment where she will test various concentrations of giberellic acid solution. She sets up five groups of twenty-five plants each. Four of the groups are watered daily with various concentrations of giberellic acid solution, the fifth with water without any additives. The length of the main root was measured every 3 days in each plant and the average of each group was recorded. The results are summarized in the data table below:

$$ \text{ Length of Main Root (cm):} $$

Plant # Conc. of IG$_3$ (ug/ml) Day 3 Day 6 Day 9 Day 12 Day 15
1 0 2 2.2 2.5 2.8 3.1
2 10 2.1 2.5 2.9 3.3 3.5
3 20 1.9 2.7 3.0 3.5 3.9
4 30 2.2 2.9 3.3 3.7 4.1
5 40 2.0 2.3 2.4 2.4 2.5

If Researcher #1 were to repeat her experiment using the exact same conditions as before, with the exception of substituting IG3 for Giberellic Acid, which statement would most likely summarize her new results?

A

Since pea and bean plants are closely related, the pea roots would grow better overall with the IG3 versus the Giberellic Acid.

B

Since pea and bean plants are closely related to each other, the pea shoots would not grow well in the presence of the IG3.

C

Since pea and bean plants are not at all related, the pea roots will grow much better in the presence of IG3 than did the bean roots.

D

Since pea and bean plants are not at all related, no direct comparison can be made.