Question

valerie designed and conducted an experiment on pothos plants, which are common houseplants. her hypothesis is that the direction of light will affect the growth pattern of a pothos plant. to test the hypothesis, she sets up two test groups of pothos plants and observes them three weeks later. the table summarizes the test groups and observations. what are the roles of the two test groups in this investigation?

test group	growth conditions	observations
2	light source comes from all directions	stems and leaves are not bent

a. both are experimental groups, and each individually shows the effect of the direction of light.
b. one is the experimental group, one is the control group, and together they show the effect of the direction of light.
c. both are control groups, but only test group 1 shows the effect of the direction of light.
d. both are experimental groups, but only test group 1 shows the effect of direction of light.

Explanation:

In an experiment, the control group is not exposed to the variable being tested, while the experimental group is. Here, Test Group 2 with light from all directions is the control (normal - no directional light effect), and Test Group 1 with side - only light is the experimental group. Together they show the effect of light direction on plant growth.

Answer:

B. One is the experimental group, one is the control group, and together they show the effect of the direction of light.