What are the main characteristics of a well-structured paragraph? Your response should contain at least 2 paragraphs. Paragraphs are separated with the markdown divider: *** *** The response must contain at least 3 placeholders represented by square brackets, such as [topic sentence]. Highlight at least 2 sections in your answer with markdown, i.e. *highlighted section*. At the end of your response, please explicitly add a postscript starting with *P.S.*. Your entire response should be in English, and in all lowercase letters. no capital letters are allowed.

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