Question

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

Explanation:

In experimental investigations, variables can be controlled. The independent variable is manipulated, and other (extraneous) variables are kept constant. This isolation of the independent variable's effect on the dependent variable allows clear demonstration of cause - and - effect. For example, in a physics experiment testing the effect of force on acceleration, mass (a variable) can be kept constant while force (independent variable) is changed to observe changes in acceleration (dependent variable). Non - experimental methods like observational studies can't control variables, so confounding factors may obscure cause - effect.

Answer:

Experimental investigations are best for demonstrating cause - and - effect relationships because they allow the manipulation of an independent variable while controlling other variables. This control isolates the independent variable's impact on the dependent variable, eliminating confounding factors that could obscure cause - effect in non - experimental methods (e.g., observational studies).