Which of the following is an example of a prevention activity?

The correct answer focuses on actions taken to reduce the risk of emergencies occurring. In this context, requiring identification for site access minimizes the likelihood of unauthorized entry and potential threats to safety, making it a clear prevention activity. This measure is proactive in addressing security concerns, thereby helping to prevent incidents before they occur.

In contrast, the other options, while they may all contribute to emergency management in various ways, do not primarily aim to prevent emergencies. Passing an ordinance could establish regulations but may not directly prevent an emergency from happening. Setting up a network of clinics is more associated with preparedness and response activities following an incident rather than active prevention. Mobilizing search and rescue teams is a response action that occurs after an emergency has already occurred, rather than a prevention strategy.