The historical era most likely referred to in this quotation is the

Most likely the industrial revolution.

Explanation: The use of machines in production became more and more prevalent, eventually many factories were built in cities which caused pollution therefore making the air gross.

answer; i believe the correct answer is (the willamete valley);

"the sepoy rebellion was the result of many, many influences and stressors on the cultures of india living under british rule. in britain, it's called the sepoy mutiny on the indian mutiny, but in india, it's called the first war of independence.

the main reason is concerned to the british paramountcy , the belief in british   dominance in india political, economic and cultural life had been introduced in india about 1820."

"they were forced to grow crops that benefited the colonizing nations instead of feeding their own people."

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explanation: