According to the NIST, what were the reasons for the collapse of the Twin Towers on September 11, 2001? List and explain a minimum of four of the reasons given in the NIST report.Your response should be at least 200 words in length. You are required to use at least your textbook as source material for your response. All sources used, including the textbook, must be referenced; paraphrased and quoted material must have accompanying citations.2.Discuss the various collapse types and the indicators that firefighters must be aware of while operating on scene of an emergency. Include the dangers associated with each type of building construction and the importance of collapse zones during response and mitigation efforts.Your response should be at least 200 words in length. You are required to use at least your textbook as source material for your response. All sources used, including the textbook, must be referenced; paraphrased and quoted material must have accompanying citations