Answer:
have fallen by more than one-half.
Explanation:
Thick, noticeable smog in many of the cities and manufacturing centers of the United States helped bring the 1970 e Clean Air Act to spur passage at the height of the national environmental movement. The ensuing modifications were intended to enhance its effectiveness and address newly recognized problems of air pollution such as acid rain and stratospheric ozone layer damage. The Clean Air Act allows EPA to set national environmental air quality levels for certain specific and prevalent contaminants, based on the latest research, to protect public health and welfare nationally. Certain main regulations are intended to reduce the rise in emissions from increasing motor vehicle numbers and new manufacturing plants.
They lived in what was normal in those times. The Islamic traders dealt with a wide variety of goods, including sugar, salt, textiles, and spices. The way that they lived back then allowed the traders to travel all the way from Europe to China. Also, they were most likely wealthy and powerful.
At present, migration continues to be a strong phenomenon in regions such as Latin America and Africa due to the poor living conditions in some countries of these regions.
<h3>What is migration?</h3>
Migration is a term to refer to the movement of an individual or group from their country of origin to other countries seeking to improve their living conditions or for other reasons.
<h3>What is the current situation of migration?</h3>
Migration is a phenomenon that is still present in society because some regions of the world do not offer good living conditions to their citizens. An example of this is Venezuela and some African countries.
<h3>How does this influence immigration policy?</h3>
Migration directly influences migration policy because the receiving countries of migrants must modify their laws to adapt the functioning of society to this phenomenon. In some countries, aid is given to migrants, while in others they are persecuted and expelled.
Learn more about immigration in: brainly.com/question/13688875
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Cold War, when the commies stoped all food from getting to Democratic Western Berlin
