Question

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Explanation:

Analyze the experimental setups

The experiment tests how planaria respond to two distinct environmental factors: water temperature and water acidity.

• Student 1 proposes using two separate groups of flatworms (one group for the temperature test, and a different group for the acidity test).
• Student 2 proposes using the same group of flatworms for both investigations.

Evaluate Student 1's method

Using Experimental Design principles, Student 1's method is more accurate. By using separate groups of planaria for each investigation, Student 1 prevents carryover effects. If the same worms are exposed to the first treatment (e.g., extreme temperature), their physiological state, health, or behavior could be permanently altered, which would skew the results of the second treatment (acidity).

Evaluate Student 2's method

Using the Scientific Method, we must control variables to ensure that only the independent variable affects the dependent variable. If Student 2 uses the same group of worms, the prior exposure to temperature changes becomes a confounding variable during the acidity test. The worms might be stressed, damaged, or acclimated, leading to inaccurate data.

Formulate the final explanation

Student 1's method is more accurate because it isolates the two experiments. Using different groups of worms ensures that the response of the worms in the second experiment is not influenced by their experiences or stress from the first experiment.

Answer:

Student 1's method would give more accurate results.

Using a different group of planaria for each investigation is the better experimental design because it prevents carryover effects or confounding variables. If the same group of worms were used for both tests (as Student 2 suggests), the stress, physiological changes, or damage caused by the first environment (such as temperature changes) could alter how those same worms respond to the second environment (acidity). Using separate groups ensures that the results of each test are independent and accurate.