Hi,

The civil services exams is conducted in 3 phases - prelims, mains and personal interview.

In prelims, there are 2 parts- General Studies and CSAT and each carry 200 marks in which the topica are mostly on Logical Reasoning, Analytical Skills, History of India, Indian and world geography, political system, governance, constitution, Social justice and IR.

In Mains exam there are 7 papers including 2 optional subjects in which you can choose subjects of your choice they include Physics, Botany, Agriculture, Phisolsophy, Sociology, Statistics, Zoology  and many more. You can choose any 2 from these subjects

Hope this helps!