Answer:
don't know lol my boy hope this helps
Answer:
A
Step-by-step explanation:
Basically, this is an observational study because the researcher does not apply any treatment.
It's not an experiment because there is no experimentation involved. :)
It's not double-blind because in that case the researcher would have to apply something to two kinds of groups. one aware one the other not. not the case.
It's not D because The observations are comparing two kinds of subjects and they are not looking for a cause and effect.
If we substitute 2 into x it'll be:
