I believe the answer is Observational study
In an observational study, the data input couldn't be controlled by researchers because it's relative to the subject.
This type of study usually being conducted in researchers that involve ethical measurement or Personal opinion.
Answer:
A sounds the best here
Explanation:
D makes no sense
C doesn’t cover everything/ main idea
B is also focusing on one part
i hate to be doing this but personally Texas new mexico Arizona and California due to a shared border with mexico
Because each child is unique so they each act differently and do stuff/complete stuff in different ways
Sorry if wrong hope this helps
Answer:
the rocky mountains
Explanation:
because its the only thing that does that lol