question_answer

Marie conducted an experiment to find out if the number of bulbs arranged in series would affect the brightness of the bulbs. Which of the following variables should be kept the same? A. type of bulbs                        B. Number of wires C. types of batteries     D. Number of bulbs

A) D only                         

B) B and D only

C) A, B and C only          

D) A, B, C and D