The set of elements—Carbon, Hydrogen, and Nitrogen—is fundamental for the origin of life on Earth because they constitute the primary building blocks of organic molecules essential for biological processes. Carbon’s ability to form stable covalent bonds with a variety of elements allows for the creation of complex molecules, such as proteins, nucleic acids, and carbohydrates. Together with hydrogen and nitrogen, these elements enable the formation of the diverse biochemical compounds that are critical for the emergence and sustenance of life, as outlined in biological and chemical principles in standard UPSC materials, including NCERT textbooks.