Answer: C. Is the maintenance of relatively stable internal environment.
Homeostasis is the ability of cells, tissues, and organs to maintain, regulate, and ensure stability of the body system while adapting to certain conditions to ensure survival. It is the maintenance of a relatively stable internal environment in the presence of external changes. Concentration of minerals, pH level, fluid balance, body temperature, etc., are certain variables which need constant regulations for every change in the external environment to maintain or preserve life. Various diseases today are as a result of failure in homeostasis. For example, if the temperature of the body goes too high or falls too low, and the body is not able to regulate this rapid change on time, it can lead to heat stroke or hypothermia which are both life-threatening.