(A) at 40 to 44 million years old provide evidence of

(B) as being 40 to 44 million years old provides evidence of

(C) that it is 40 to 44 million years old provides evidence of what was

(D) to be 40 to 44 million years old provide evidence of

(E) as 40 to 44 million years old provides evidence of what was

答案是D，用estimated的用法就选出来了，但是有一个问题没弄懂，OG上解释说provide和fragments 主谓一致，但是我没有看懂这句话的结构。

Paleontologists believe that  fragments （of a primate jawbone  ) unearthed and estimated (to be 40 to 44 million years old )provide……

因为有and 连接，所以  unearthed 和estimated并列，那provide在这儿又是什么意思呢，为什么是fragments的谓语呢，看不懂结构了。本人语法白痴，问了个很笨的问题，恳请教NN们指教