A study is being done on a group of people to decide the harm of fast food to the body. The patients have their own choice on whether or not they choose to eat the food and the doctors just observe the results. What type of sample or survey is this? A. observational study B. self-selected C. controlled experiment​

Where’s the following prism

The answer of the above question is

In all honesty, there really is no “work” per say to show. mainly it’s just using the process of elimination. the question is asking which domain(s) would be the most appropriate for the function c(n). n is the number of observed vehicles so right away, 1, 2, and 3 can be eliminated.why? 1, 2 start in the negatives and therefore it is impossible to observe negative cars. so, #4 would be the best answer to the given problem.

Your answer should be 1/3. i hope i could ! good luck : )