You are interested in researching the effects of vitamin c on colds. for your study, you round up a group of people, all roughly the same age and healthy. you give them all vitamin c pills to take every day and have them check in with you once a month to see if they get a cold. why is this not a good study design

the research study lacked a control group, It was  difficult to know individuals who are not taking  Vitamin C and exposed to cold

Explanation:

Normally in a research study there should  be a control group of the same age group like the study group in the same environment, who will not  Vit, C but a   placebo. To determine if Vitamin. C is   the  actual effective drug for prevention of cold  in the study group or other factors.

Therefore, in this study It was  difficult to know individuals who were not taking  Vitamin C and exposed to cold(control group) Because, it is the comparison of the  data from the control  group and the study groups  that is  needed to determine the efficacy of Vitamin C

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

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