Which of the following should be done when designing an experiment for a controlled scientific investigation?

A.

list the procedures

B.

plan the variables

C.

list the needed materials

D.

all of these

D - All of these should be done

The correct answer is letter D.

Explanation:

A controlled scientific investigation is manipulated by a scientist. The intention is to examine a single variable at a time. To do so, it is necessary to have as much control as possible over the experiment and the environment. Listing the procedures, planning the variables, and listing the needed materials are all necessary to design an experiment.