Final answer:
Defendants against a tort action may use legal defenses such as the doctrine of supervening event, the government contractor defense, and an expired statute of limitations.
Step-by-step explanation:
In the context of law, the legal defenses mentioned in the question are typically used in a civil action called a tort.
The doctrine of supervening event refers to an unforeseen event that occurs after the defendant's alleged negligent act, which relieves them of liability. The government contractor defense provides immunity to government contractors for injuries caused by products that meet specific requirements. An expired statute of limitations means that the plaintiff did not file the lawsuit within the time limit set by law.