The White House is defending President Donald Trump's chief of staff after he mischaracterized previous remarks of a Democratic congresswoman who is now criticizing Trump's condolence call to the widow of a soldier killed in Niger.John Kelly on Thursday derided Rep....
Dinosaurs lived throughout the Mesozoic Era, which began 245 million years ago and lasted for 180 million years. It is sometimes called the Age of the Reptiles. The era is divided into three periods.45 to 208 million years ago. 1  During the Triassic period, all land on Earth existed as one enormous mass. 2  It was called Pangaea. 3  The supercontinent slowly began to break up during the Triassic Period.
Some argue that humans began changing the global environment about 50,000 years back, in the Pleistocene epoch, helping along if not outright causing the mass extinctions of megafauna, from mammoths to giant kangaroos, on most continents. Others date it to the emergence of agriculture some 7,000 years ago.he beginnings of burning fossil fuels to power machines in the 19th century initiated a change in the mix of atmospheric gases, and the first nuclear weapon test on July 16, 1945, spread unique isotopes across the globe.