The maintenance of a constant internal environment in an organism is known as

1. Analyze the question The question asks for the term describing how an organism keeps its internal conditions (temperature, water, blood sugar, pH, etc.) steady despite changes outside.

2. Explain the concept Break the word down: homeo = similar or constant, stasis = standing or staying. So homeostasis means "staying the same internally." It includes:

• Regulation of body temperature (thermoregulation)
• Osmoregulation (water and salt balance, done by the kidneys)
• Regulation of blood sugar (insulin and glucagon)
• Excretion of metabolic wastes

3. Check each option

• A. Homeostasis is the maintenance of a constant internal environment. This matches the question exactly.
• B. Homoiothermy is the ability to maintain a constant body temperature (warm-blooded animals such as humans and birds). It is only one example of homeostasis, not the whole concept, so it is too narrow.
• C. Diuresis is the production of increased amounts of urine. It is not the general term.
• D. Dialysis is the artificial removal of waste from the blood, for example with a kidney machine. It is a medical treatment, not a natural process.

4. Answer The correct option is A. homeostasis.

5. Exam tip Watch for the trap between homeostasis and homoiothermy. Homoiothermy deals only with temperature, while homeostasis covers everything about the internal environment. If the question says "constant internal environment" in general, choose homeostasis. If it says "constant body temperature," choose homoiothermy.