Thanks to science, industry and moral philosophy, mankind's steps were at last guided up the right path in the past century. The 19th century of steam was about to give way to the 20th century of oil and electricity. Charles Darwin's theory of evolution, only 41 years old in 1900, provided a scientific basis for the idea that progress was not to be stopped, determined by natural law. And almost everybody thought that the development would continue to be as slow as that in the 19th century. Inventions like the railroad or the telegraph or the typewriter enabled people to live their everyday lives a little more conveniently. No one could have guessed that new ideas would storm the world with a force and frequency at an amazing pace. This high-speed attack of new ideas and technologies seemed to make people believe in the old dreams of a perfect life on earth, of a safe world in which natural disasters would be controlled. But the fast progress was accompanied by something against mankind's will. Murders in Sarajevo  in 1914 led to the Great War, which did more than destroy a generation of Europeans. The Great War was most commonly called so until the beginning of World War II when it was renamed World War I. Hitler rose to power in the 1930's. It was this very man who ordered the attack of prefix = st1 /Poland, only to meet with his failure whenGreat BritainandFrancemade war onGermany. On December 7, 1941, the Japanese bombed the American naval base at Pearl harbor. Americans decided to enter the war, and World War II was now truly a world war. But civilization was not crushed  by the two great wars, and from the ruins people built a way of life again. The citizens of the 20th century felt free to reinvent themselves. In that task they were aided by two far-reaching developments-Psychoanalysis  and the Bomb. It can be inferred from the passage that at the beginning of the 20th century   _  .
great changes occurred between the 19th century and the 20th century the world knew nothing about science, industry and moral philosophy mankind came to realize there was not a change in the 19th century Darwin, the builder of the theory of evolution, was in his forties