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from north from south from west from east
Scientists used wrong guidelines of mathematics. Scientists used wrong building materials. Scientists used different operating systems. Scientists used different measurement systems.
was discouraged was enforced by law was prohibited by law was introduced
To develop a specific research interest and become professional scientists. To send their research observations to a professional database. To increase their knowledge about climate change. To keep a record of their research observations.
By analyzing the data published in journals like Nature and Ambio. By observing the lead accumulations in different parts of the arctic area. By studying the chemical elements of soil and snow in Northeastern America. By comparing the chemical compositions of leaded gasoline used in various countries.
the; the /; the /;/ the; /
forests get rid of lead pollution faster than expected lead accumulations in forests are more difficult to deal with lead deposits are widely distributed in the forests of the US the upper layers of soil in forests are easily polluted by lead emissions
are puzzled by the mystery of forest pollution feel relieved by the use of unleaded gasoline still consider lead pollution a problem lack sufficient means to combat lead pollution
To study when plants will have their first buds. To find out the types of plants in the neighborhood. To collect life cycle data on a variety of common plants from across the United States. To investigate how plants and animals will respond as the climate changes.
the Clean Air Act has not produced the desired results lead deposits in arctic snow are on the increase lead will stay in soil and snow longer than expected the US is the major source of lead pollution in arctic snow
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