There are two types of GRE tests - the GRE subject test (subjects include Physics, Biology, Chemistry, Mathematics, Psychology, and English Literature) and the GRE general test (Analytical Writing Assessment, Verbal Reasoning, and Quantitative Reasoning). Additionally, paper-based tests are not available everywhere; they are available only where computer-based tests aren't available. GRE subject tests are only available on paper. It is available at over 1000 test centres across 160 countries.