What is one of the physical traits of a Jack Russell Terrier?

The physical trait of a Jack Russell Terrier that is identified as strong and muscular build accurately reflects the breed's overall appearance and function. This breed is known for its athleticism and agility, traits that come with a well-developed body structure. They are energetic and built for endurance, which contributes to their performance in various activities such as hunting, agility competitions, and other dog sports.

Attributes like a strong and muscular build are essential for a working dog, facilitating their capability to navigate diverse terrains and execute tasks efficiently. Therefore, recognizing this characteristic helps in understanding the breed's purpose and design, which is rooted in their origin as hunting and working dogs.

In contrast, while the other options may represent various dog traits, they do not capture the quintessential aspect of the Jack Russell Terrier's physique as precisely as a strong and muscular build does.