Chemical substance identity of benzene, until the correct structure was described by Friedrich August Kekulé. Likewise, the idea of stereoisomerism – that atoms have rigid three-dimensional structure and can thus form isomers that differ only in their three-dimensional arrangement – was another crucial step in understanding the concept of distinct chemical substances. For example, tartaric acid has three distinct isomers, a pair of diastereomers with one diastereomer forming two enantiomers. An element is a chemical substance made up of a particular kind of atom and hence cannot be broken down or transformed by a chemical reaction into a different element, though it
Internet-related prefixes Internet-related prefixes Internet-related prefixes such as "e-", "i-", "cyber-", "info-", "techno-" and "net-" are added to a wide range of existing words to describe new, Internet- or computer-related flavors of existing concepts, often electronic products and services that already have a non-electronic counterpart. The adjective "virtual" is often used in a similar manner. "Cyber-" is derived from "cybernetic," which comes from the Greek word κυβερνητικός meaning "skilled in steering or governing". It is mainly used in the terms "cyberspace", "cyberlaw", "cyberbullying", "cybercrime", "cyberwarfare", "cyberterrorism", "cybersex", and "cyberdelic" among others. Although it is more commonly used to describe policies and politics