Find the odd domestic animal (pet vs livestock): Choose the option that is primarily kept as a companion animal rather than for milk or meat.

Introduction / Context:
Another stable separator in basic zoological reasoning is human use or role. Livestock are raised for agricultural products such as milk or meat, whereas pets are kept for companionship, security, or herding but not primarily as food production animals.

Given Data / Assumptions:

• Cow: livestock, primarily milk and meat in many regions.
• Goat: livestock for milk and meat.
• Camel: livestock and draught animal; milk and transport in arid regions.
• Dog: primarily a companion, working, or guard animal; not standard livestock for dairy or meat in most contexts.

Concept / Approach:
Group by agricultural production role. Three options are livestock species commonly raised for milk or meat; dog is primarily companion or working animal.

Step-by-Step Solution:

Verification / Alternative check:
Check typical farm outputs: milk and meat arise from cow, goat, and camel husbandry; dogs do not provide such outputs in standard agriculture.

Why Other Options Are Wrong:
They share the livestock production role.

Common Pitfalls:
Guard or herding roles of dogs do not convert them into livestock; role category is distinct.

Final Answer:
Dog