1. Even after you eat a sweet dessert, the level of glucose in your blood stays relatively constant. This is an example of , the maintenance of relatively constant internal conditions despite fluctuations in the external environment. 2. The maintenance of internal water and solute concentrations within a narrow range is called . 3. The maintenance of internal temperature within a narrow range is called . 4. A(n) , such as a pigeon, is an organism that gains body heat primarily from its own metabolism. 5. A(n) , such as a salamander, is an organism that gains body heat primarily by absorbing it from the environment. 6. The disposal of nitrogen-containing wastes, as through urination, is called .