Final answer:
The three elements required for the employment of deadly force are ability, opportunity, and jeopardy, each relating to capacity, chance, and immediate threat to life, respectively.
Step-by-step explanation:
To answer the question about the three elements that must be present for deadly force to be employed, we need to consider specific criteria typically used in legal and law enforcement contexts. In general, the use of lethal force is permissible when the following three conditions are met: ability, opportunity, and jeopardy. Ability refers to the subject's capacity to cause serious harm or death. Opportunity concerns the subject having a clear chance to use their ability to cause harm. Lastly, jeopardy relates to the circumstance where an innocent person's life is in immediate danger, necessitating the use of deadly force to prevent harm.