Ornithothoraces Ornithothoraces Ornithothoraces is a group of avialans that includes all enantiornithes ("opposite birds") and the euornithes ("true birds"), which includes modern birds and their closest ancestors. The name Ornithothoraces means "bird thoraxes". This refers to the modern, highly advanced anatomy of the thorax that gave the ornithothoracines superior flight capability compared with more primitive avialans. This anatomy includes a large, keeled breastbone, elongated coracoids and a modified glenoid joint in the shoulder, and a semi-rigid rib cage. The earliest known members of the group are the enantiornitheans "Protopteryx fengningensis", "Eopengornis martini", and "Cruralispennia multidonta", as well as the euornithine "Archaeornithura
What If?: Serious Scientific Answers to Absurd Hypothetical Questions What If?: Serious Scientific Answers to Absurd Hypothetical Questions What If?: Serious Scientific Answers to Absurd Hypothetical Questions is a non-fiction book by Randall Munroe in which the author answers hypothetical science questions sent to him by readers of his webcomic, "xkcd". The book contains a selection of questions and answers originally published on his blog "What If?", along with several new ones. The book is divided into several dozen chapters, most of which are devoted to answering a unique question. "What If?" was released in September 2, 2014 and was received positively by critics. In the introduction section of