我觉得OG这里说E是平衡的,是指由于使用的是分号,所以从they开始引领的是另一个完整的句子,这样从句子结构上来说和前面的句子平行。
[Tropical bats play important roles in the rain forest ecosystem, aiding in the dispersal of cashew, date, and fig seeds]; [they pollinate banana, breadfruit, and mango trees; indirectly helping the producing of tequila by pollinating agave plants.]