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
What More Can I Give and the International Child Art Foundation. The charities support arts programs to eliminate racism, increase education and connect children throughout the world, respectively. The download project had been set up by Jackson with the American media company Clear Channel Communications.<ref name="Michael Jackson's Troubled 9/11 Single Now A Charity Download"></ref> Footnotes Bibliography What More Can I Give "What More Can I Give" (also "Todo Para Ti" in Spanish) is a song written by American singer Michael Jackson and recorded in 2001 by Jackson and a supergroup of singers following the September 11 attacks. The inspiration for the song had initially come