The significance of answer writing practice for UPSC Mains lies in its ability to enhance clarity and coherence in responses. Regular practice enables candidates to manage time effectively during the exam and develop a structured approach to answering questions. It helps in refining writing speed, articulation of thoughts, and use of relevant examples. Moreover, feedback on practice answers provides insight into weaknesses, allowing for targeted improvements. Practicing diverse topics fosters confidence and familiarity with the exam format, ultimately leading to improved performance in the Mains examination.