Physical Security discussion 3

Using proper APA formatting write 400-600 words, not including your heading or reference pages discussing the significance of the following:    What are natural protective barriers? List and explain at least three What are structural protective barriers? List and explain at least three List and explain at least four reasons protective barrier should be established. Requirements    In-text citations and a reference list are also a requirement. You need to have at least 8 cited sources. Please ensure that all cited sources are credible.