Which term describes maintaining boundaries between the internal and external environments?

• A. Organization
• B. Movement
• C. Responsiveness
• D. Digestion

Answer: (A)

Maintaining boundaries between the internal and external environments is tied to the organized, structured nature of living beings. Organization refers to how the body’s components are arranged from cells up to organs and organ systems in a way that creates and preserves separate compartments. This organized setup includes boundary membranes—like cell membranes and epithelial layers—that regulate what can enter or leave, helping keep the internal environment stable despite changes outside. The other options describe activities (moving, reacting to stimuli, digesting food) that are about function, not about creating or preserving those boundaries. So the organized arrangement best fits the idea of boundary maintenance.