Cells & Body Systems Crossword

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Across
  1. 2. two main branches of the trachea that lead into the lungs (singular bronchus)
  2. 3. blood vessels that return blood from the body to the heart; have valves
  3. 4. group of tissues that work together to perform a specific function
  4. 5. finger-like projections on the cells that line the villi (singular microvillus)
  5. 7. tubes that connect the bronchi to the air sacs in the lungs
  6. 9. physical breakdown of food into small particles
  7. 12. made of just one cell
  8. 15. any change in an organism's environment
  9. 16. large muscle below the lungs that helps move air in and out of the lungs; part that changes the size of a camera’s aperture; it varies the amount of light that reaches the film
  10. 17. cell fragments in the blood that help stop bleeding at cuts
  11. 18. organism's reaction to stimulus
  12. 20. small, plioable cells that have no nucleas and are specialized for carrying oxygen to all the cells of the body
  13. 21. the basic unit of life
  14. 22. group of similar cells working together to perform a specific function
Down
  1. 1. of connective tissue found in the body that produces red blood cells
  2. 3. small finger-like projections on the inner surface of the small intestine that absorb nutrients (singular villus)
  3. 6. transport system reaching every cell in the body
  4. 8. blood cells specialized to fight infection
  5. 9. made of more than one cell
  6. 10. breakdown of large food particles into smaller particles by enzymes
  7. 11. cells that have specific structures that help them to perform particular functions
  8. 13. thick-walled blood vessels that take blood away from the heart to the rest of the arteries
  9. 14. group of tissues that work together to perform a certain task
  10. 19. wave-like muscle contractions along the digestive system