Give an example of a single-celled organism.

How is oxygen absorbed in single-celled organisms?

What is a single-celled organisms body surface covered by?

Single-celled organisms have no barriers to the diffusion of gases, why?

What two features do insects have to reduce the amount of water lost?

Why is it hard for an insect to reduce water loss?

What is the pathway for diffusing gases out of an insect?

How is the trachea given strength in insects?

Where do the tracheoles extend through in an insect?

In which two ways do respiratory gases move in and out of an insects tracheal system?

How can ventilation speed up respiratory rate in insects?

How do gases move in and out of insects?

How do the spiracles open and close?

What are the limitations of an insects tracheal system?

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