Some examples is the holocaust in 1933 and Armenia 1915
The three characteristics of a nation is a population, borders, and recognition from the other nations. For example Taiwan has a border and population but isn't recognised by NATO and the UN so it is still technically part of China. <span />
Answer:
The right answer is B.
Explanation:
Rotation of crops is a very old farming technique, used already in ancient times in different places such as China or in the Roman Empire. It is not an innovation of the 19th century, unlike the other three things mentioned here.