When you breathe, your lungs take in ___ and remove ___. 

• air/oxygen
• oxygen/carbon dioxide 
• carbon dioxide/waste 
• waste/air 

Organs of the respiratory system that bring oxygen-rich air into​ ​the body and send oxygen-poor air out of the body.

• heart
• muscles
• lungs
• bones

The process of taking in oxygen and releasing carbon dioxide from the body.

• transpiration 
• respiration 
• digestion
• relaxation

The tube in the body through which air moves as it travels to and from the lungs;the windpipe.

• heart
• bone
• blood vessel
• trachea 

Tiny air sacs in the lungs that are the site of gas exchange between the lungs and blood.

• alveoli​
• relax
• diaphragm​
• nose

A wide muscle that separates the chest cavity from the abdominal cavity and aids in the inflation of the lungs.

• diaphragm​
• heart
• nose
• trachea

The beginning point of the respiratory system where air is taken into the body.

• lung
• diaphragm​
• nose​
• trachea​

What is the main function of the respiratory system?

• to provide oxygen and remove carbon dioxide from the body
• to bring oxygen to the body
• to break down food and absorb nutrients
• to remove oxygen from the body and deliver carbon dioxide

What are the main organs of gas exchange in the respiratory system?

• diapragm
• lungs
• trachea
• bronchi

How do your circulatory and respiratory systems work together?

• Your heart protects your lungs

• Lungs bring food into the body for your blood

• Oxygen and carbon dioxide are exchanged between your lungs and blood.

• The respiratory system makes blood for your circulatory system