The correct answer is C :)
The main way in which the railroads contributed to the end of the large buffalo herds was that "The railroad tracks were obstacles that the buffalo would not cross". It sounds silly, but the buffalo actually refused to cross the tracks for reasons that are still misunderstood.<span />
Answer: Fifty five percent of the land in Africa is unsuitable for any kind of agriculture except nomadic grazing. ... About 16% of the land has soils of high quality and about 13% has soils of medium quality.
