Questions: How is the concept of homeland security defined b

Questions: How is the concept of homeland security defined by at least three different authors and does the difference in the definition affect the overall goal to protect the homeland? How does homeland defense overlap with homeland security and identify the challenges?Instructions: Fully utilize the materials that have been provided to you in order to support your response. Your initial post should be at least 500 words.http://apus.libguides.com/er.php?course_id=6105