In what way can stress negatively impact an animal's health?

Stress can have significant negative effects on an animal's health, primarily by leading to behavioral issues and immune system suppression. When an animal is stressed, it can exhibit changes in behavior that may manifest as aggression, fearfulness, or withdrawal. These behavioral changes can impact the animal's quality of life and may complicate training or socialization.

Additionally, chronic stress can suppress the immune system, making the animal more susceptible to diseases and infections. The release of stress hormones, such as cortisol, can inhibit the function of immune cells, reducing the body's ability to respond effectively to pathogens. This weakened immune response can result in a higher likelihood of illness and may prolong recovery times for existing conditions.

In contrast, the other options do not accurately reflect the effects of stress on health. Stress does not generally have no serious effects; rather, its impact is profound. It also does not increase appetite and energy levels, as stressed animals often display reduced appetite and lethargy. Furthermore, stress is not beneficial for recovery from illness; instead, it can hinder the healing process due to the impairment of immune function. Thus, recognizing how stress affects animal health is crucial for proper care and management.