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
The World Is What It Is in 1996. The biography has been extensively reviewed: the reviewers include Paul Theroux, who wrote an earlier book about Naipaul. The biography was selected by the editors of the "New York Times Book Review" as one of the "Times"' "10 Best Books of 2008". It won the 2008 National Book Critics Circle Award in Biography, and the British literary award the Hawthornden Prize. The World Is What It Is The World Is What It Is: The Authorized Biography of V. S. Naipaul is a biography of the Nobel Prize-winning author V. S. Naipaul by Patrick French. It was published in