Description should include examples of

untreatable/irreversible medical conditions that cause suffering (e.g., uncontrollable pain or distress, inability to eat or drink, inability to breathe without difficulty, organ failure due to gradual build-up of toxins)
irreversible, intolerable behaviors (e.g., unmanageable viciousness toward humans or other animals, other behavior that poses a serious health risk to humans or other animals).

Process/Skill Questions:

When might euthanasia be an option for a pet with cancer or other chronic illness?
When might the government require an animal be euthanized?
Why must an animal that has bitten a human be quarantined before it is euthanized?
Why might an entire herd have to be euthanized if some of the animals test positive for a disease?
Why is animal euthanasia an ethical issue?
Why do some veterinarians refuse to euthanize healthy animals?
Why is it imperative to have the legally required documentation in order before performing euthanasia?