In an experiment, you test whether the number of times you rub a cloth against a balloon changes how long it will stick against the wall. You start by rubbing the balloon 10 times with the cloth and stick it to the wall. You repeat this three times and record your results in a table. Observation
Number of Times Balloon is Rubbed by Cloth Trial #1 Trial #2 Trial #3
10 6 seconds 20 seconds 20 seconds
What statement best reflects why you should do repeated trials in an experiment? (2 points)

a
Rubbing the balloon against a cloth 10 times produces very different results each time it is repeated.

b
The first trial is right because it is done with new materials that give the best results.

c
The second and third trials were wrong because they were very different from the first trial.

d
You would make a wrong conclusion if it were based on the first trial in the experiment.

Oxygen and nutrients are moved through the body by the: a. circulatory system c. lymphatic system b. digestive system d. reproductive system

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