Explain how the structure of the trachea serves to protect the lungs.  Be sure to include what type of cells line the trachea in your response.

Why are females more susceptible to urinary tract infections?

Which of the following are organs of the urinary system?  Select all that apply.

Explain the difference between internal and external respiration.

Letter A in the diagram below is pointing to which structure?  

The duodenum is part of which structure?

What is the function of structure C in the diagram below?  

This flap of tissue prevents food from passing into the larynx while swallowing:

Calcium and sodium are both trace minerals needed in our diet.

The thick, soupy liquid of partially digested food and gastric juice that leaves the stomach is called: