In scientific experiments, when conducting extreme stress tests on animals, researchers usually follow certain ethical standards and experimental design principles. Such experiments can help us understand the physiological and psychological responses of organisms under extreme environments or stress. Here are some common methods and steps: 1. **Select a suitable animal model**: Select appropriate animal species according to the purpose of the study, such as mice, rats, macaques, etc. The selected animals should have good experimental adaptability and be physiologically and genetically related to the stress factors involved in the study. 2. **Design an experimental plan**: Develop a detailed experimental plan, including the objectives of the experiment, the type of stress (such as physical stress, psychological stress, environmental stress, etc.), stress intensity, application time, and observation indicators. 3. **Pressure application**: - **Physical stress**: Observe the response of animals to extreme conditions by changing environmental conditions (such as temperature, humidity, air pressure, etc.). - **Psychological stress**: Stress can be applied through social isolation, limiting activity space, or using threatening stimuli (such as the sound of predators). 4. **Monitoring physiological responses**: Observe and record the physiological changes of animals after stress is applied, such as heart rate, respiratory rate, body temperature, hormone levels (such as cortisol), etc. 5. **Behavioral observation**: Assess the behavioral responses of animals, including anxiety, depression, social behavior, etc. Common methods include open field experiments, forced swimming tests, social interaction experiments, etc. 6. **Data analysis**: Collect experimental data and use statistical methods to analyze the responses of animals under different stress conditions. This can help determine the limit of stress and its impact on animals. 7. **Follow ethical standards**: Ensure compliance with ethical principles of animal experiments, including minimizing animal pain and anxiety, using appropriate anesthesia and analgesia, and humane treatment after the study. Through the above steps, researchers can effectively use animal models to study the effects of extreme stress on organisms, thereby providing important scientific basis for understanding human responses in similar situations.