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 Is Love? (EP) What Is Love? (EP) What Is Love? (stylized as What is Love?) is the fifth extended play (EP) by South Korean girl group Twice. The EP was released on April 9, 2018 by JYP Entertainment and is distributed by Iriver. It includes the lead single of the same name produced by Park Jin-young. Twice members Jeongyeon, Chaeyoung, and Jihyo also took part in writing lyrics for two songs on the EP. The reissue of "What Is Love?", titled "Summer Nights", was released on July 9, 2018. On February 26, 2018, JYP Entertainment confirmed that Twice planned to release a new