Question

a student was measuring the height of plants grown with different types of fertilizer or with plain water. he took his measurements using inches, then realized that he needed to use metric units, so he converted his measurements from inches to centimeters. what is the control group in this experiment?

plant	measurement in inches	measurement in centimeters
b	5	?
c	7.2	?
d	2	?

multiple choice

• a plant that was not watered with anything
• the type of plant
• the plant watered with only water
• plant d because it is the shortest

Explanation:

In an experiment, the control group is the one that does not receive the experimental treatment (here, different fertilizers) and is used for comparison. The plants with plain water (no fertilizer) serve as the control to compare with plants given fertilizers. The first option is invalid as plants need water; the second is a variable, not a group; the fourth is incorrect as height doesn't define the control.

Answer:

C. the plant watered with only water