Final answer:
Animals must not be left unattended after being given a euthanasia agent until death, in accordance with AVMA guidelines to ensure a humane process.
Step-by-step explanation:
The statement that animals may not be left unattended between the time the euthanasia agent is given and the time of death is generally considered to be true. According to the American Veterinary Medical Association (AVMA) guidelines for the euthanasia of animals, it is important that the process is monitored by a qualified individual to ensure that it is carried out humanely and effectively. Monitoring is necessary to address any complications that may arise during the process and ensure the animal does not suffer. Particularly in legal contexts, such as in countries where euthanasia is regulated, strict adherence to these guidelines is expected.