UPSC Combined Defence Services Exam papers Download previous years. After you are done with you preparation tries to solve CDS Model question paper. Eligible Applicants can apply for Online Application. Written Exam has tree of English, General Knowledge, and Elementary Mathematics. Combined Defence Services Answer Key Union Public Service Commission conducts the Combined Defence Services exam on October 23, 2016. This one of toughest competitive exams in India, so preparation is must to clear this exam.