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 need to be summarized in a research article for submission to a peer-reviewed nutrition journal.
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 are not meaningful or valid because of the way she designed her study.

Question

Quizplus · Accepted Answer

The researcher added only one type of mineral (cadmium) to the diet of the mice, which means that there was no control group or comparison group. Without a control group, it is impossible to know if the effects observed were due to the cadmium, or some other factor. Additionally, the fact that the mice lost weight and had abnormal hormone levels could be indicative of health problems that were not related to the cadmium intake. Therefore, the findings are not meaningful or valid due to the way the study was designed.

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