Which of the following is a behavioral indicator of fear, anxiety, or stress in horses?

Flat ears is a behavioral indicator of fear, anxiety, or stress in horses because this position signals discomfort or unease. When a horse's ears are pinned back flat against its head, it is often a response to perceived threats or stressors, indicating that the horse is feeling threatened or agitated. This body language is an important part of equine communication and helps handlers recognize when a horse is not comfortable in its current situation.

In contrast, calm behavior typically suggests that the horse is relaxed and not experiencing fear or anxiety. Vocalization, while it can indicate a range of emotions, including stress in some contexts, is less definitive as a behavioral indicator compared to ear position. Active movement can indicate excitement or eagerness and does not specifically denote fear, anxiety, or stress. Understanding these cues is crucial for effectively managing and caring for horses in a way that promotes their well-being.