Instances where you would expect to find when comparing two different variables

Using your creativity, share specific instances where you would expect to find when comparing two different variables a strong, positive correlation, a very weak correlation, and no correlation at all. Secondly, why do researchers insist that you cannot show causation when doing correlation?
Discussion Question: Must be at 250 words.
Read: Ravid, R. (2020). Practical statistics for educators (6th ed.). Rowman & Littlefield Publishers. ISBN: 9781475846836. Read chapters 7 & 8.
After reading the textbook, explain the difference between a simple linear regression and a multiple regression. Next, explain a useful multiple regression that you could complete using data from your present occupation.