Trachea to air sacs. Many insects, such as grasshoppers and bees, which actively pump the air sacs in their abdomen, are able to control the flow of air through their body. In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of a gill, or function essentially as normal, via a plastron. Note that despite being internal, the tracheae of arthropods are lined with cuticular tissue and are shed during moulting (ecdysis). In 2008, a Colombian woman, Claudia Castillo (30), received a trachea transplant using her own stem cells. Between 2011 and 2014 Paolo Macchiarini
What Work Is terribly damaged conditions of American labor, whose circumstance has perhaps never been more wrecked.” After Levine was named Poet Laureate, "What Work Is" reached the top of Amazon.com's "Movers and Shakers" list. What Work Is What Work Is is a collection of poetry by Philip Levine. The collection has many themes that are representative of Levine's writing including physical labor, class identity, family relationships and personal loss. Its primary focus on work and the working class led to it being studied with emphasis on Marxist literary criticism. The focus on work is expressed in thematically different ways throughout the collection.