The main cause of most wildfires started in Utah each year is human activity. To arrive at this answer, we can eliminate the options that are not relevant and focus on the remaining choices. In this case, we can eliminate "controlled burns" and "lightning" since these are not the main causes. To confirm if the correct answer is "human activity," we can consider factors such as the presence of humans in the affected areas, accidental or intentional acts that could spark a fire, and statistical data on the causes of wildfires in Utah. By analyzing these factors, we can conclude that human activity is indeed the main cause of most wildfires started in Utah each year.
