A more thorough explanation:

Definition: Border control is a way for a country to show that it has control over its land and who enters and leaves it. It is used to regulate the movement of people and goods across the border. Border control is important for preventing the spread of diseases, fighting terrorism, and catching criminals.

Examples:

• Checking passports and visas at airports and border crossings
• Inspecting cargo at ports to make sure no illegal goods are being smuggled
• Using sniffer dogs to detect drugs or explosives

These examples show how border control is used to regulate the movement of people and goods across a country's border. By checking passports and visas, a country can make sure that only authorized people are entering the country. Inspecting cargo helps prevent illegal goods from entering the country. Using sniffer dogs helps detect drugs or explosives that could be used for criminal or terrorist activities.