懂你英语流利说Level4 Unit2 1/4 Vocabulary

The body's circulatory system includes the heart and blood vessels.

The heart pumps blood to all parts of the body through a network of arteries and veins.

The digestive system breaks down and absorbs food into the body.

It's supplies the energy that the body needs for growth and repair.

After digestion,execss food is turned into waste and eliminated from the body.

The nervous system includes brain spinal cord and nerves.

This is your body contral system.

It contral your musuls and orgens including your sequrtry and digestive  system.

The nervous system regulates your heartbeat and digestion

The respirtory system includes the nose and lungs.

It brings air and oxygen into the body and removes carben dioxide .

The lungs are where oxygen enters the bloodstream and carben dioxide is removed.

The immune system protects the body against infections and diseases.

Sneezing and fever are example of how the immune system works.

If an infection invades body the immnue system attacks it.

For some diseases,the immune system uses whites blood cells antibodies to attack it.

The blood vessels that carry oxgen-rich blood from the heart are called arteries.

---

The controlled use of fire allowed people to cook food and survive in the colded 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 growing food,people could spend less time hunting and more time for other things such as art.

The ability to herds of animals supply humans a regular hunt of meat and colthing.

The strength of animals such as horses and oxen was used for work and transportation.

With better tools and machines,work can be done with fewer people and at much lower costs.

The use of machines has reduced the number of people needed to make things.

With the development of agriculture, people had more time for other activities.

The digestive system is where food is broken down and absorbed into the body.

Science and engineering have changed the way we communicate with each other

Science and engineering breakthroughs are rapidly changing the way we live our lives.