Scientists perform a study looking at the effects of caffeine on vertical jump performance. On one day, they give all the subjects caffeine followed by vertical jump tests. Two weeks later, they give all the subjects a placebo followed by the same vertical jump tests. Which term best describes this study design

explanation:

may i ask what challenges?

hello,

answer: a federal government has final authority on interstate/inter provincial  and international affairs, a confederation is one where the central/national government or authority is governing body what does not have final say over the same matters. hopefully this and i will try again if you don't like this answer : )

best of luck!

answer; community based corrections;