Question

groups of students conduct an experiment to determine whether lettuce plants produce more leaves under red, or green light. the groups collect the following data.

group 1	color of light	number of leaves
	red light	63
	blue light	115
group 2	color of light	number of leaves
	green light	14
	red light	31
	blue light	72

which would be an appropriate limitation of the model associated with the different groups regarding the light?
a group 1 did not use a control, but group 2 did.
b group 1 used repeated trials and group 2 did not.
c group 1 had more people on the team than group 2
d group 1 used a brighter light than group 2.

Explanation:

To determine the appropriate limitation, we analyze each option:

• Option A: The experiment's design (testing different light colors) implies both groups should have a control (e.g., same light intensity, duration, plant type). But the data doesn't show Group 2 using a control while Group 1 doesn't—this is inconsistent.
• Option B: The data shows the number of leaves for each light color in both groups. If Group 1 repeated trials (increasing sample size) and Group 2 didn't, Group 1's larger leaf counts (e.g., 32 vs 14 for green, 63 vs 31 for red, 115 vs 72 for blue) could be due to more trials, making this a valid limitation.
• Option C: The table doesn't provide information about the number of people (or plants) in each group, so we can't conclude this.
• Option D: The table doesn't mention light brightness, so this is not supported.

Answer:

B. Group 1 used repeated trials and Group 2 did not.