Homeostasis is defined as

Explanation

The question is asking about the definition of homeostasis. Homeostasis is the maintenance of a stable internal environment in an organism despite changes in the external environment. This means that the organism tries to keep its internal conditions, such as temperature, pH, and glucose levels, within a narrow range that is optimal for its survival. Option A states that homeostasis involves the regulation of both external and internal conditions of organisms. Although organisms do regulate their external conditions to some extent, this is not the definition of homeostasis. Option B is correct. It correctly defines homeostasis as the maintenance of the internal environment of an organism. Option C states that homeostasis involves the maintenance of both internal and external environments of an organism. This is not the correct definition of homeostasis as it only involves the maintenance of the internal environment. Option D states that homeostasis involves the regulation of the chemical environment of an organism. Although homeostasis does involve the regulation of chemicals in the body, this is not a complete definition of homeostasis. In summary, the correct definition of homeostasis is the maintenance of a stable internal environment in an organism despite changes in the external environment.