Because Slate was more common in wet microclimates.
Hope I Helped :)
On this day in 1914, as World War I erupted across Europe, President Woodrow Wilson declared that the United States would remain “impartial in thought as well as in action.” ... In February 1915, Germany declared unrestricted warfare against all ships, neutral or not, that entered the war zone around Britain.
Answer:
Great Britain, France, the Soviet Union, and the United States
The Apartheid government of South Africa resulted in the forced removal of 3.5 million black South Africans between 1960 and 1986. This all white government made legal segregation possible in South Africa. This forced millions of individuals to move and started segregated public facilities. During this era, there was very little contact between white and black South Africans.
