Without what critical assessment on an animal, you can't arrive at a diagnosis?

A physical examination is essential for arriving at a diagnosis because it involves a hands-on assessment of the animal's body systems. This examination allows the veterinarian or veterinary technician to detect signs of illness, injury, or abnormalities that might not be evident through other means. During a physical examination, key indicators such as vital signs, physical condition, presence of pain, and any abnormalities in the body can be evaluated. This vital information helps in formulating a preliminary diagnosis and guides further diagnostic processes such as laboratory tests or imaging.

Other assessments, while important, play supportive roles in the diagnostic process. For instance, behavior analysis can provide insights into the animal's emotional and mental health, and medical history can reveal past health issues or treatments. Laboratory tests can confirm diagnosis through specific data related to blood, urine, or other bodily fluid analysis. However, none of these can replace the fundamental information gathered during a thorough physical examination.