Final answer:
The changes in an experiment attributed to a treatment variable are related to the dependent variables, which are the effects or outcomes being measured. Researchers must control extraneous variables to ensure that any observed effect is due to the independent variable's manipulation.The correct answer is d) Dependent variables.
Step-by-step explanation:
The correct answer is d) Dependent variables.
Researchers conducting experiments must control for extraneous variables so that any modifications in the dependent variable can reliably be attributed to the manipulation of the independent variable. The dependent variable is what is measured in the experiment; if researchers wish to determine the effect of ginkgo biloba on memory and concentration, these cognitive aspects are the dependent variables. They need to ensure that the changes seen in memory and concentration are indeed due to the treatment with ginkgo biloba, without being influenced by confounding or extraneous factors.
To achieve this control, researchers may use a control group, random assignment to treatment groups, and possibly a placebo. These strategies help to establish a clear cause-and-effect relationship between the independent variable (ginkgo biloba treatment) and the dependent variable (changes in memory and concentration) by eliminating the influence of other variables that could potentially affect the outcome.