Cells Circulatory digestive endocrine Excretory nervous tissues Muscular organs Respiratory Skeletal systems 5. 1. are the basic building blocks of living organisms. Cells work together with similar cells and form 2. which in turn These tissues then combine to form 3. are connected together in organ 4. Your lungs, for example, are part of the system, which is responsible for bringing oxygen into your body and releasing carbon dioxide into the atmosphere. Your heart is part of the 6. system, which is responsible for circulating blood containing food and oxygen to all of the cells in your body. Your stomach is part of the system, which is responsible for breaking down food so that your cells can use it. Your kidneys are part of the 8. system, which is responsible for eliminating waste from your body. Your bones are part of the 9. system, which give your body structure. Your muscles are part of the 10. system, which allows your body to move. Your brain is part of the 11. which controls muscle movement and your senses. Finally, your glands are part of the 12. system, which produces hormones that regulate your body. 7.​