What is the purpose of the Department of Homeland Security?
a to prevent immigration into the United States
b. to put together a coalition to combat terrorist in Afghanistan and Iraq
to protect the country from future terrorist attacks
to find illegal immigrants living in the United States and deport them

find illegal immigrants living in the United States and deport them

Explanation:

Department of Homeland Security works in the civilian sphere to protect the United States within, at, and outside its borders. Its stated goal is to prepare for, prevent, and respond to domestic emergencies, particularly terrorism.

The United States Department of Homeland Security (DHS) is a federal agency designed to protect the United States against threats. Its wide-ranging duties include aviation security, border control, emergency response and cybersecurity.

The Department of Homeland Security secures the nation's air, land, and sea borders to prevent illegal activity while facilitating lawful travel and trade