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.
The peripheral nervous system is divided into two major parts: the somatic nervous system and the autonomic nervous system. SOMATIC NERVOUS SYSTEM contains peripheral nerves that help in body movements. it contains efferent and afferent nerves. Efferent nerves takes impulses away from nervous system Afferent nerves brings impulses to the nervous system AUTONOMIC NERVOUS SYSTEM controls involuntary actions such as breathing,heartbeat and digestive system.