og 2, 不明白e选项；og 5 的代词指代

2. Since 1981, when the farm depression began, the number of acres overseen by professional farm-management companies have grown from 48 million to nearly 59 million, an area that is about Colorado's size.

(E)   has grown from 48 million up to nearly 59 million, about Colorado's size

og 的解释说E选项的错误是：The absence of an area in B and E impairs clarity: the phrase beginning with about must modify a noun such as area that is logically equivalent to the number of acres given。

不明白 area 怎么可以和 the number 。。。对等？

5.正确答案：

Carbon-14 dating reveals that the megalithic monuments in Brittany are nearly 2,000 years   older than any of their supposed  Mediterranean predecessors.

不明白any of their supposed  Mediterranean predecessors应该怎么译，their 是Mediterranean predecessors？

请xdjm指教。谢了

我的理解：the number of acres given虽第一眼看上去象是数量词，但其实这是一个面积概念，就好像说“俺们家乡的刘大地主有六千亩地”呢一样。

any of their supposed  Mediterranean predecessors，their指the megalithic monuments 吧？说的是这些在B岛的巨石经检测比他们任何一个假想的M的祖先（巨石）都要早。supposed与Mediterranean一起修饰prededessors.

thx,