What process refers to the body's ability to maintain internal stability?

The correct choice highlights the concept of homeostasis, which refers to the body's ability to maintain a stable internal environment despite external changes. This involves various physiological processes that regulate body temperature, pH levels, hydration, and more, ensuring that the body functions optimally.

Homeostasis is essential for survival; it allows the organism to make dynamic adjustments to internal conditions—such as altering heart rate or respiration—to respond to external stimuli. This careful regulation enables the body to function effectively, thereby promoting overall health and well-being.

In contrast, metabolism pertains to the chemical reactions involved in maintaining cellular functions, growth relates to the increase in size or number of cells, and reproduction involves processes that enable species continuation through the creation of offspring. While all these functions are vital to biology, they do not specifically address the overarching regulatory function that homeostasis embodies.