Complete the crossword, then click on "Check" to check your answer. If you are stuck, you can click on "Hint" to get a free letter. Click on a number in the grid to see the clue or clues for that number.

	1									2					3			4
					5										6
7	8
								9						10
11				12									13
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				15
16																				17
				18
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	20
21													22
			23															24
25							26
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		28

 Check 

Across: 1. animals without backbones 3. breathing organs in water 5. living things which make food by photosynthesis 7. Passes on genes from mother to new baby 9. Helps to keep mammals warm in the winter 10. "Instructions" for making features 11. Invertebrates with six legs and a body in three parts 14. The many 'sections' some invertebrate bodies have 15. Sensory 'feelers' on the head of some invertebrates 16. Vertebrates with wings made of feathers 18. Invertebrates with eight legs and a body in two main parts 19. Differences between living things 21. Vertebrates with dry skin and hard non-overlapping scales 22. A group of the same living things which can breed together successfully 23. With a constant body temperature 25. The joining of the nuclei of sperm and egg, or pollen and egg 27. Of features which are due to living conditions 28. With a varying body temperature

Down: 2. Vertebrates which can live both in water and on land 4. Breathing organs on land 6. Passes on genes from father to new baby 8. Of features which are passed on from parents 12. Sorting living things into groups 13. Descriptions of living things 17. Vertebrates with gills and fins, which live in water 20. Provide birds with insulation 24. Vertebrates which suckle their young with milk 26. A snail's hard protective case