The Great Wall of China was built to protect China from its enemies and invaders from the North, especially the Mongols (Mongols were a tribal group that would regularly conduct raids into China) the Great Wall of China was built in the 7th century BC and is located in Huairou District, China! Hope this helps
Answer:
approximately 1.002 billion
Explanation:
the combined population of both north and south america is approximately 1.002 billion
Belgium,Denmark, Poland, Austria, France, Norway, The Netherlands, Czechoslovakia
Answer:
The presence in the air of one or more contaminants in such a concentration and of such duration as to cause a nuisance or to be injurious to human life, animal life or vegetation.