Pratchett is known for a distinctive writing style that included a number of characteristic hallmarks. Resilience is a common and normal human characteristic. It is a defining characteristic of mammals. It is typically a secondary sex characteristic of human males. They have at least one singular characteristic. Races are defined according to any identifiable characteristic, including gene frequencies. Each element has electronic orbitals of characteristic energy. These structures demonstrated pores of sizes characteristic to diatom patterns. Biologists have yet to discover the purpose of this unique characteristic. The other important characteristic is charge density. Each chemical bond in a molecule vibrates at a frequency characteristic of that bond. Perseveration is a common communicative and behavioral characteristic in FXS. This is equal to the topological Euler characteristic of its surface. A salient characteristic of modernism is self-consciousness. They shared a common characteristic, Humanism.