Why is normalization an important step in database developme

Why is normalization an important step in database development?What would you give as a broad description of normalization?Does normalization dictate the database physical design, why or why not?What are BCNF, 4NF, and 5NF used for, when are they used?Why would denormalization be applied; provide an example? provide three to four pages covering above topic with in-text citations and references and make sure no plagarisiam