Question

A scientist adds 5 mcg of the mineral cadmium to the daily diet of 100 4-week-old laboratory mice. After twelve weeks, the researcher weighs and takes blood samples from each mouse. According to her findings, the mice lost weight during the 12-week period and they have abnormal levels of certain hormones in their blood. Based on this information and your knowledge of scientific research, what would you tell the researcher about her findings?
A. She needs to conduct more tests on the animals' blood, because her findings are
incomplete.
B. The findings are not meaningful or valid because of the way she designed her study.
C. Her results are very interesting and she should report her findings to nutrition scientists, so
they can repeat her study and confirm the results.
D. The findings need to be summarized in a research article for submission to a peer-reviewed
nutrition journal.

Answer 1

Answer:

B. The findings are not meaningful or valid because of the way she designed her study.

Explanation:

In a scientific experiment, a control group is a group of individuals/subjects that do not receive the experimental treatment. The control group is used to determine how much of an impact a treatment (in this case, cadmium intake) has on the variables being examined in the participants who are subjected to the experimental treatment. In any experiment, it is imperative to include a control group in order to validate experimental results. In this case, it is not possible to confirm that the loss of weight and abnormal hormone levels are due to cadmium uptake because only a control group would elucidate the contribution of cadmium intake on the variables being tested.