sentence2_structure: the muscular and skeletal organs<>are known as<>the musculoskeletal system
sentence1: The organ systems to be studied are integumentary, skeletal, muscular, endocrine, neuro-sensory, digestive, respiratory, circulatory and urogenital systems.
sentence2: Together, the muscular and skeletal organs are known as the musculoskeletal system.
question: Together, the muscular and skeletal organs are known as what?