Homeostasis is

Options

A. a tendency to change with change in environment
B. tendency to resist internal changes
C. disturbance in regulatory controls
D. plant and animal extracts used in ho- meopathy

Answer

**Step-by-Step Solution:**

1. **Definition of Homeostasis**: Homeostasis refers to the process by which living organisms maintain a stable internal environment despite changes in external conditions. This involves the regulation of various physiological parameters such as temperature, pH, and ion concentrations.

2. **Importance of Homeostasis**: Homeostasis is crucial for the survival of organisms. It allows cells and organs to function optimally, ensuring that metabolic processes occur efficiently.

3. **Examples of Homeostasis**:
- **Respiratory System**: The lungs help maintain oxygen levels in the blood by facilitating gas exchange. They provide oxygen to the extracellular fluid, which is then delivered to cells.
- **Renal System**: The kidneys regulate the concentration of ions and waste products in the blood, ensuring that the internal environment remains stable.
- **Digestive System**: The gastrointestinal system absorbs nutrients from food, contributing to the maintenance of energy levels and overall health.

4. **Evaluating Options**:
- **Option 1**: "A tendency to change with change in environment" - This is incorrect as homeostasis involves maintaining constant conditions.
- **Option 2**: "A tendency to resist internal changes" - This is correct as homeostasis aims to minimize internal fluctuations.
- **Option 3**: "Disturbance in regulatory controls" - This is incorrect since homeostasis seeks to avoid disturbances.
- **Option 4**: "Plant and animal extracts used in homeopathy" - This is unrelated to the concept of homeostasis.

5. **Conclusion**: The correct answer is that homeostasis is characterized by a tendency to resist internal changes, which is essential for maintaining a stable internal environment.