Answer:
The correct answer is "6".
Step-by-step explanation:
The data gathered from an experiment of plants growing in soil containing worms (Experimental Group) in comparison of plants growing in soil without worms (Control Group) show an apparent effect of the presence of worms in the average height of the plants. It can be noted by the data herein attached, that after five weeks, the plants growing in soil containing worms grew an average of 6 centimeters taller than the plants in the control group, as it is shown in the row entitled "Difference in Average Height".