1) The document focuses on species extinction as described in an 8th standard Biology textbook. It discusses the major causes of species extinction such as deforestation, hunting, overexploitation, introduction of exotic species, and global warming. 2) Some examples of extinct species given are the Dodo bird which became extinct due to hunting and many Harlequin frog species in Central and South America that disappeared due to infectious diseases caused by climate change. 3) There have been 5 major extinction events in history including at the end of the Ordovician, Devonian, Permian, Triassic, and Cretaceous periods.