The word which means "can be helpful or harmful depending on the point of view" is beaver. Beaver can both have a good and a bad effect to the ecosystem. In a good point of view, beaver serves as natural filters segregating sediments from flowing to bodies of water. On the other hand, it can also cause flooding.
Early American settlers just wanted more land and personal space, so they moved west of the Appalachians. Later, this extended to the belief that it is American destiny to expand to the Atlantic Ocean. <span>
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1921 belongs to time where the juridical base was formed as a result to demands of the growing economic environment
The answer to your question is c
