Final answer:
The most frequently used method of execution in the United States currently is lethal injection.
Step-by-step explanation:
The most frequently used method of execution in the United States currently is lethal injection. Lethal injection involves administering a combination of drugs, typically a sedative to induce unconsciousness, followed by drugs that stop the heart and cause paralysis. Despite recent controversies and challenges, lethal injection remains the primary method of execution in the country.