Name two environmental conditions that must be maintained within specified ranges to ensure animal welfare in laboratories.

• A. Temperature and humidity.
• B. Temperature and light intensity.
• C. Humidity and airflow.
• D. Light cycle and airflow.

Answer: (A)

Maintaining ambient conditions within species-appropriate ranges supports physiological stability and reduces stress. Temperature and humidity are the two environmental factors that must be kept within specified ranges. If the ambient temperature drifts too far from the comfortable zone, animals experience thermal stress that can alter metabolism, behavior, feeding, and immune function. Humidity affects hydration of mucous membranes, respiratory comfort, and skin condition; extremes in humidity can dry or dampen tissues, increasing irritation and susceptibility to illness. By keeping these two parameters within target ranges, welfare is supported and experimental variability is reduced. While light-related factors and airflow are also important for welfare, temperature and humidity form the foundational controls most universally required across facilities.