Farmer brown believes that increasingly large doses of antibiotics will produce increasingly large beef cattle. what is the correct match between experimental variables and activities in farmer brown's experiment?
a. dependent variable; all cattle receive the same hay, water, and living quarters.
b. control variable; different groups of cattle are given different doses of antibiotics.
c. independent variable; farmer brown tests only antibiotic x in even incremental dosages.
d. hypothesis; farmer brown observes that dosage with 500 mg of antibiotics produces the most weight gain.