Why are experimental investigations prove to be the best type of scientific investigation to demonstrate cause-and-effect relationships?

I believe the answer is: because we can study the cause - and - effect relationship between different variables in a controlled environment.

In a controlled environment, we can freely change the factors that might influence the result whenever we want, in order to cross check whether a certain factor would resulted in the desired effect or not. This includes conducting test to test hypothesis and validity of the claims.

the answer is: tabard inn, southwark.

in "the canterbury tales," by geoffrey chaucer, the twenty-nine diverse group of pilgrims is staying at a tavern in southwark, london, as they are traveling to canterbury. they wish to visit the relics of saint thomas becket in canterbury   cathedral in order to him for his when they underwent necessities.

i think the literacy device is "it's frozen head"