b) blocking pathogens that cause diseasesThe integumetnary system includes skin, hair, & mucous membranes, all of which are responsible (in part) for blocking disease-causing pathogens from entering the blood streamIT CANNOT be A b/c the circulatory system distributes vital substances through the bodyIT CANNOT be C b/c the lymphatic system sends leaked fluids from the cardiovascular system back to the blood vesselsIT CANNOT be D b/c the reproductive system stores bodily hormones that influence gender traits