All of these are necessary, but what you need the most I would say is
D. Movement
Without movement, your body can stiff up, causing muscle problems which can lead to many various things.
Answer: D. His conclusion is flawed because he did not test the students to see if their bodies contained metal arsenic.
Explanation:
According to the given situation, student has tested seven different areas around the school to determine the presence of arsenic in the soil and also found the presence of arsenic in the school system. But has not studied the presence of arsenic in the students to support the fact that the school students are also affected by arsenic. So, conclusions based on the presence of arsenic in the soil and the system is inconclusive for the present study.
