Kidneys were the first organs to be transplanted successfully. A donor can live a normal life with a single kidney, making it possible for individuals to donate a kidney to an ailing relative or even an unrelated individual. In some countries, poor people sell kidneys to transplant recipients through organ brokers. What are the pros and cons associated with organ commerce?

Fish and other aquatic organisms are exposed to many types of water pollutants, including metals such as aluminum. Although a low level of aluminum is found in unpolluted water, many lakes and streams have an increased level because of mining, sewage treatment, and accidental spills of toxic materials. Aluminum pollution can result in mass fish die-offs.True or false: Water moves by osmosis across a fish's gills to an area with a higher sodium ion concentration because water molecules are attracted to the sodium ions.

Compare the water and salt regulation in a salmon when it swims in the ocean to when it migrates into fresh water to spawn.

Fish and other aquatic organisms are exposed to many types of water pollutants, including metals such as aluminum. Although a low level of aluminum is found in unpolluted water, many lakes and streams have an increased level because of mining, sewage treatment, and accidental spills of toxic materials. Aluminum pollution can result in mass fish die-offs.Draw a graph similar to the one here showing how the results would be different if the experiment had been performed on marine bony fish in seawater. (Assume that the osmolarity of seawater is 1100 mOsm and the set point osmolarity of marine bony fishes is 290 mOsm.)

Two endothermic animals are the same size, but one is a carnivore and the other is an herbivore. Predict which of these animals would produce the greatest amount of nitrogenous wastes. Explain.

Scientists have found that the quantity of aquaporin molecules inserted in the membranes of collecting duct cells changes in response to ADH levels. Draw a line graph proposing a relationship between ADH levels and its effect on the quantity of aquaporins. Additionally, explain how the relationship between ADH and aquaporins corresponds to situations of dehydration and hydration.

An albatross spending its life hovering over the ocean provides an extreme example of __________, the process by which animals control solute concentrations and balance water gain and loss.

Osmoconformers are animals that __________.

In a marine environment, animals that are isoosmotic relative to their environment __________.