How we get civil rankers which subjects are main

Hello,

Are you enquiring about UPSC Civil Service Exam, if yes then the exam is conducted in three stages namely;

Preliminary is the first Stage, it's MCQs based exam, it has two papers and each one consists of 200 marks, its numbers ain't added to final list, you just need to score the required cut offs against your category.

• First is GS Paper-I which consists of the following topic such as History of India and Indian national movement, Indian and World geography, Economic and social development- sustainable development, poverty,inclusion demographics, social sector initiatives etc,Indian polity and governance-constitution,political system,Current Events nationally and Internationally, General Science,General Issues on environmental ecology,biodiversity and climate change. you just need to score the required cut offs against your category.
• Second Paper is CSAT which is qualifying by nature, you need to score merely 33% which is 66 marks out of 200, it includes following topics such as basic numeracy, comprehension, logical reasoning and analytical ability, general mental ability, decision making and problem solving, interpersonal skills including communication skills.

Mains: This is a second stage which it's more of a subjective type, you are required to write answers for Four General Studies Paper such as

• GS-I includes Indian Heritage and Culture, History and Geography of the World and Society,
• GS-II includes Governance, Constitution, Polity, Social Justice and International Relations,
• GS-III includes Technology, Economic Development, Bio-Diversity, Environment, Security and Disaster Management,
• GS-IV includes Ethics, Integrity, and Aptitude
• Two Optionals,
• One Essay,
• Two Language Paper

In total there are nine papers in Mains, and each paper is of 250 marks, total adds up to 1750 marks.

Prelims and Mains are further followed by personality test of 275 marks.

When it comes to UPSC as I mentioned prelims numbers aren't added, still everything is important in this exam, you can't skip any subject, but yes one of the important thing is you don't have to be an expert in each subject, but your base or foundation should be definitely strong in all the subjects, this is because questions come from such diverse background, and hence it's highly recommended to make the base strong by going through NCERTs, this help a lot, hence be well acquainted with UPSC syllabus, you should have enough decent understanding of all the topics that should get reflected in your answer writing in mains especially, and this does require a lot of practice of mock papers and detailed analysis of previous  year paper.