In animals, nitrogenous wastes are produced mostly from the catabolism of

The advantage of excreting wastes as urea rather than as ammonia is that

Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species?

The following questions refer to the digestive system structures in Figure 41.1. Figure 41.1 Which structure is home to bacteria that produce vitamins as by-products of their metabolism?

A freshwater fish was accidentally placed in salt water. After several minutes in this saline water, it died. What is the most logical explanation for its death?

Which structure descends deep into the renal medulla only in juxtamedullary nephrons?

In 2012 a British teenager celebrated her birthday by drinking a cocktail made with liquid nitrogen and alcohol.  The liquid nitrogen froze her stomach, and her stomach had to be removed surgically.  Given what you know about the function of the digestive tract, what potential implications might removing a person’s stomach have for that person’s ability to digest food?  What might that person now have to consider doing to ensure proper nutrition?   Explain your reasoning.

You are a drug manufacturer that has designed a new drug that is taken in capsule form.  You want the drug to be delivered to the small intestine.  You have to decide if the capsule coating the drug should be made of carbohydrate, fat or protein such that you get optimal delivery of the contents to the small intestine.  Which would you choose?  Explain your choice and the rationale behind it.  

The following questions refer to the digestive system structures in Figure 41.1. Figure 41.1 Where does the digestion of fats mostly occur?

Women who are especially susceptible to urinary tract infections should