Did you know that invertebrates don't have backbones? Find out some different types of invertebrates with the clues in this crossword puzzle.

Use clues to fill in the boxes in this crossword puzzle, and learn more about freshwater fish along the way.

Test your knowledge of prehistoric animals with this life sciences crossword puzzle!

What's the animal that swims upstream? Help your child figure this out with this cold-blooded animal crossword puzzle worksheet.