Trachea Diffusion of oxygen and carbon dioxide takes place across the walls of the smallest tubes, called tracheoles, which penetrate tissues and even indent individual cells. Gas may be conducted through the respiratory system by means of active ventilation or passive diffusion. Unlike vertebrates, insects do not generally carry oxygen in their haemolymph. This is one of the factors that may limit their size. A tracheal tube may contain ridge-like circumferential rings of taenidia in various geometries such as loops or helices. Taenidia provide strength and flexibility to the trachea. In the head, thorax, or abdomen, tracheae may also be connected
Less Commonly Taught Languages individuals interested in less commonly taught languages" founded in 1990 and based at the Indiana University Bloomington. The Council's mission is to increase the number of Americans who choose to learn one or more of the less commonly taught languages (LCTLs) as a means of enhancing cross-cultural communication among citizens of the United States . ... The Council seeks to improve the teaching and learning of these languages and to make them more generally available. The Council is the national voice for organizations and individuals who represent the teaching of these less commonly taught languages at both the collegiate and