Unit 2

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Across
  1. 5. Movement of water across a partially permeable membrane
  2. 7. Upper chambers of the heart that receive blood
  3. 9. Heart chamber that pumps blood out of the heart
  4. 10. Blood vessel that carries blood away from the heart
  5. 13. Network of vessels connecting arteries and veins
  6. 14. Specialised muscle found only in the heart that contracts without fatigue
  7. 16. A group of organisms that can interbreed to produce fertile offspring
  8. 17. Movement of air into and out of the lungs
  9. 19. Protein that carries oxygen in red blood cells
Down
  1. 1. Movement of molecules from high to low concentration
  2. 2. The variety of life in a particular habitat
  3. 3. A system in fish where water flows in the opposite direction to blood
  4. 4. A community of organisms and their physical environment
  5. 6. The total area available for gas exchange
  6. 8. Iron-containing part of haemoglobin that binds oxygen
  7. 11. Tube that carries air to and from the lungs
  8. 12. Blood vessel with a large lumen and valves
  9. 15. Tiny air sacs in the lungs where gas exchange occurs
  10. 18. Number of times blood passes through the heart in a double circulatory system
  11. 20. Structures in fish gills that increase surface area for gas exchange