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In 1970, rate for autism was 4 per 10,000 (1 case per 2,500 births). By 1997, the rate was 31 per 10,000 (1 case per 323 births), a 774 percent increase
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RAINFOREST
Depending on the height of the thick trees, rainforest grow in layers. At the top, where the tallest trees pop out is the emergent layer. The canopy, which is beneath the thick treetops, fans out like an umbrella. Down below is the understory made up of smaller trees. Little or no sunlight reaches the dark and gloom forest floor
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