never
it occurred in 1912
Yes, although mutations are rare, they are still present today meaning that they were also present during the 20th century.
Vatican I occurred during the 19th century, not 20th.
Yes, the warmest years of the 20th century actually occurred in the late 1990s. Data shows that the years 1997, 1998, and 1999 were among the warmest years of the 20th century.
The Russian Revolutions all occurred in the first twenty years of the 20th century.
This occurred in the early 20th century.
The final major eruptions of the 20th century occurred in 1986 and in 1999.
Cubism started in 1908 - not in the late 20th century, so there is no answer to your question.
In the 20th century, May 13th fell on a Friday in the years 1921, 1927, 1932, 1938, 1949, and 1955. Additionally, it occurred again in 1960, 1966, 1977, and 1983. The last occurrence of May 13th falling on a Friday in the 20th century was in 1988.
20th century
in the 20th century in the 20th century
For the 20th Century; probably the exodus from Vietnam that occurred from 1975 upward.