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)Her results are very interesting and she should report her findings to nutrition scientists,so they can repeat her study and confirm the results.
B)The findings need to be summarized in a research article for submission to a peer-reviewed nutrition journal.
C)She needs to conduct more tests on the animals' blood,because her findings are incomplete.
D)The findings are not meaningful or valid because of the way she designed her study.

Question

Quizplus · Accepted Answer

The researcher only added one variable (cadmium) to the mice's diets, and there was no control group. Without a control group, it is impossible to determine if the weight loss and abnormal hormone levels were caused by the cadmium or something else entirely. Therefore, the researcher's findings are not meaningful or valid, and she needs to redesign her study with a control group.

A Scientist Adds 5 Mcg of the Mineral Cadmium to the Daily