North America and Europe are in the midst of a large-scale ...

[mia]

North America and Europe are in the midst of a large-scale experiment. Sulfuric and nitric acids have acidified soils, lakes, and streams, thereby stressing or killing terrestrial and aquatic biota.(365) Assess this statement.
 
  What is meant by the word experiment here?

Question 2

It is thought that the ancestors of most Europeans originally shared the Mongolian plateau with the mongolian peoples of Asia.
 
  It is also known that the Hittites, the Scythians, and the various Aryan invaders of India came from that region over quite a long timespan. This area is now the Gobi desert. Advance scenarios for the historical migrations of these various peoples.

[jazzlynnnnn]

Answer to Question 1

This statement is saying that the release of SO2 and NOx from smokestacks of
(mostly) coal-fired power plants has resulted in concrete harm to wildlife and fish. The
experiment is the construction and use of these SO2 and NOx emitters without due
consideration of the consequences of the emissions or concentrated effort to reduce or
reverse what is being done.

Answer to Question 2

Most likely desiccation was responsible for the invasions. If the land were
originally bountiful, it could support a large population. If the population grew too great for
the land to supply with food, the extra people could turn into marauders and leave for other
places. As the land dried out, farmers would have had to leave their lands. Eventually, the
land would become too dry for pasture, sending more people moving out. Any scenario
built on these bases should be acceptable.