Which example most clearly describes a system maintained by homeostasis?

• A. A growing child will deposit new bone rapidly until the endocrine system signals the end of puberty.
• B. During the 'fight-or-flight' response, the sympathetic nervous system causes a change in many physiological factors from increased blood pressure to decreased pain response.
• C. Humans typically have 46 total chromosomes, 23 from inherited from their biological mother and 23 from their biological father.
• D. Blood osmolality is maintained by the kidneys in a range from about 290 to 300 mOsm/kg.

Answer: (D)

Verified step by step guidance

1. Understand the concept of homeostasis: Homeostasis refers to the body's ability to maintain a stable internal environment despite changes in external conditions. It involves various physiological processes that regulate factors such as temperature, pH, and solute concentrations.
2. Identify the key characteristic of homeostasis: A system maintained by homeostasis typically involves regulation within a narrow range, with mechanisms in place to correct deviations from this range.
3. Analyze each example provided: Consider whether each example describes a process that involves maintaining a stable internal environment through regulatory mechanisms.
4. Evaluate the example of blood osmolality: Blood osmolality refers to the concentration of solutes in the blood. The kidneys play a crucial role in maintaining blood osmolality within a specific range (290 to 300 mOsm/kg) by adjusting the excretion of water and solutes.
5. Conclude why blood osmolality is an example of homeostasis: The regulation of blood osmolality by the kidneys exemplifies homeostasis because it involves maintaining a stable internal environment through precise physiological control mechanisms.