Body Systems
The body's circulatory system includes the heart and blood vessels.
The heart pumps blood to all parts of the body throught a network of arteries and veins.
The digestive system breaks down and absorbs food into the body.
It supplies the energy that the body needs for growth and repair.
After digestion, excess food is turned into waste and eliminated from the body.
The nervous system includes the brain, spinal cord and nerves.
This is your body's control system.
It controls your muscles and organs, including your circulatory and digestive systems.
The respiratory system include the nose and lungs.
It brings air and oxygen into the body and removes carbon dioxide.
The lungs are where oxygen enters the bloodstream and carbon dioxide is removed.
The immune system protects the body against infections and diseases.
Sneezing and fever are examples of how the immune system works.
If an infection invades the body, the immune system attacks it.
For some disease, the immune system uses white blood cells and antibodies to attack it.
Great Discoveries
The controlled use of fire allwed people to cook food and servive in colder climates.
Fire provided light so that people could work and socialize for longer hours.
With the invention of agriculture, people could grow food and settle into communities.
By grwoing food, People could spend less time hunting and more time for other things such as art.
The domestication of animals allowed people to raise and use animals for food and work.
By raising herds of animals such as sheep humans had a regular supply of meat and clothing.
The strength of animals such as horses and oxen was used for work and transportation.
The development of tools and machines has resulted in more efficient manufacturing and construction.
With an understanding of electricity, telephones and radios allow people to communicate over long distances.
The use of machines has reduced the number of people needed to make things.
Science and engineering breakthroughs are rapidly changing the way we live our lives.
With the development of argriculture people had more time for other activities.
The ability to raise herds of animals gave humans a regular supply of meat and clothing.
