According to PHS, all animals should be housed in a manner that __________ and __________.

• A. provides them with companionship; allows them to interact with others of the same species
• B. facilitates the expression of species-specific behavior; minimizes stress-induced behaviors
• C. provides them with mental and physical stimulation; promotes the expression of colony behaviors
• D. mimics natural conditions; optimizes dominance-submission hierarchies

Answer: (B)

The main idea being tested is that housing for laboratory animals should support natural, species-specific behaviors and reduce stress. This aligns with welfare standards and the PHS Policy, which require environments that allow animals to express typical behaviors (like foraging, nesting, social interactions where appropriate) and minimize stress that can lead to abnormal behaviors or poor well-being. The best answer states that housing should facilitate expression of species-specific behavior and minimize stress-induced behaviors—this captures both the ability to perform natural activities and the avoidance of distress that can undermine welfare and data quality. Other options talk about natural conditions or dominance dynamics or emphasize enrichment in a way that isn’t universally applicable across all species, making them less accurate general requirements.