Passage Two阅读理解The wold health

Passage Two阅读理解The wold health
The World Health Organization estimates （估计） 20,000,000 babies are born too small each year. It says a baby weighing less than 2,500 grams at birth has a less than desirable weight for good health. 95 percent of such children are born in developing countries.
One recent study shows that pregnant （怀孕的）women in developing countries have healthier babies if the women are given vitamins. Researchers from the United States and Tanzania found that vitamins could help reduce low birth weight. Their findings were reported last month in The New England Journal of Medicine.
wafaiem fawzia of the Harvard School of Public Health led the study. Professor fawzia says low birth weight can cause serious health problems in babies. He says low birth weight has been linked to poor growth and mental development, and even early death.
There are fourteen kinds of vitamins. People who do not get enough of these chemicals in their food, or want more, often take multivitamins （多种维生素）.In the study, multivitamin pills were given to 4,200 pregnant Tanzanian women.The pills contained all
the vitamins,as well as vitamins C and E. They also embodied iron and other nutrients in levels several times higher than advised for women in industrial nations.
Four thousand other women received a harmless substance（物质）. None of the women had the virus that causes the disease AIDS.
68．On what condition can pregnant women in developing countries have healthier babies?
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69．According to fawzia, what results will low birth weight lead to?（回答次数不超过10个）
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70．What is the main idea of the passage?（回答次数不超过8个）___________________________________________________________________ ________。