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introduces effective ways to improve memory. emphasize the importance of exercising the brain analyze the difference between different age groups in the loss of memory reveals the decrease in mental ability of the young adults as well as the older adults
in their early teens in their mi-sixties in their mid-twenties in their early thirties
was discouraged was enforced by law was prohibited by law was introduced
They lose their memory at a slower rate Their brains can store much more information They rarely realize they have memory problems They are more likely to remember false information
has found out has been found out have found out have been found out
have found, from polluting have found, from being polluted have been found, from being polluted has been found, from being polluted
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.
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
Mental performance can be improved Mental ability is determined entirely by brain structure People of different ages use different parts of the brain for memorizing Different parts of the brain are responsible for different mental activities
were found was found has found have found
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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