e correlational designs lacking

1) What 3 things do you need in order to determine causation, and what are correlational designs lacking

2) Does multiple regression allow you to determine causation, given the ability to control for third factors?

3) What research claims have you seen in the media related to treatments for COVID-19? Are they based on experimental data, or some other methodology? Knowing what you do about correlation designs, do you think that the source of the information is accurately representing the information?