The human body is very organised and has a number of organ systems.
Humans reproduce sexually.
What you will learn in this chapter: zz
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Humans are consumers and have a digestive system for breaking down food.
Humans have a circulatory system for transporting substances around the body.
The respiratory system lets humans exchange gases with the atmosphere.
Sexual reproduction in humans happens when a male sperm fertilises a female egg.
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With the exception of identical twins, why are all humans different?
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Can you crack this code?
The first letter of each image spells out a key word you will come across in this chapter. Use the hints provided if you need to, or revisit the Puzzler after you finish this chapter.