Which of the following is the minimum level of structure needed to perform the function of waste removal?
 a. body system 
 b. tissue 
 c. cell 
 d. organ C Which two systems work with the muscular system to allow the body to move?
 a. digestive and urinary 
 b. skeletal and nervous 
 c. integumentary and endocrine 
 d. immune and lymphatic B