Aluminium versus aluminum. Following up a Topical Words piece on the international spelling of what British English writes as sulphur, many American subscribers wrote in to ask about another element with two spellings: aluminium.
The simplest and presumably most primitive form of nervous system is termed a nerve net. In a nerve net, neurons are dispersed in a thin layer, not clustered into nerves or a central nervous system (CNS), and they are positioned seemingly at random relative to each other.he simplest and presumably most primitive form of nervous system is termed a nerve net. In a nerve net, neurons are dispersed in a thin layer, not clustered into nerves or a central nervous system (CNS), and they are positioned seemingly at random relative to each other.
We have an involuntary nervous system called the Autonomic Nervous System (ANS), which contains two types of nerves. 1  Parasympathetic nerves conserve energy and keep the systems in a relatively resting state. 2  Sympathetic nerves prepare the body for action through the Fight-or-Flight reaction.