The earliest introduction of zebra mussels in united states probably occurs in 1986.
At that time, commercial vessels from Europe went to north America as a place for freshwater ballast stowaway. They merchants then introduced zebra mussels to the market and it gained popularity ever since. They also introduced zebra mussels population in local lakes and let them reproduce there.
The answer is subsidy.
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The second one because it says it on the definition
Answer:
B. The melting-pot theory
Explanation:
The melting-pot theory emphasizes the combination of the parts into a single whole.