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This test is run by .
Note that your final mark will not be saved in the system.

9. Gas exchange systems Reorder

Running Total

Attempt

1 of 3

Drag and drop the boxes into the correct order.

A person breathes in.

Arrange these sentences in the correct order to describe how oxygen reaches the person's body cells.

The oxygen diffuses out of the alveoli and into the bloodstream, where it binds to the red blood cells.
Oxygen molecules diffuse out of the blood and into body cells that are low in oxygen.
The oxygen is carried around the body in the blood.
Then it enters one of the bronchi and travels into a lung.
At the end of the bronchioles are tiny air sacs called alveoli, surrounded by blood capillaries. This is where gas exchange happens.
Air containing oxygen goes in through the nose and down the throat.
Inside the lung the air passes through smaller and smaller bronchi into tiny tubes called bronchioles.
It travels down the person's trachea.

This is your 1^st attempt! The marking algorithm gives more marks for getting the right order first time.

Pass Mark

70%