What is the main difference between negative and positive feedback? a. Positive feedback leads to system instability, while negative feedback leads to system stability. b. Positive feedback is caused by human impact while negative feedback occurs naturally. c. Negative feedback ultimately leads to an increase in the first variable while positive feedback ultimately leads to a decrease in the first variable. d. Positive feedback occurs at a much faster rate than negative feedback. Please select the best answer from the choices provided A B D