求助一道prepp07语法题目：Complex human traits such as artistic talent or social skill are

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求助一道prep07语法题目：


Complex human traits such as artistic talent or social skill are likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so genes in the human genome.

(A) such as artistic talent or social skill are likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so
(B) such as artistic talent or social skill are likely shaped by thousands, if not tens of thousands, of 80,000 or so of the
(C) such as artistic talent or social skill is likely to be shaped by thousands, if not tens of thousands, of 80,000 or so of the
(D) like artistic talent or social skill is likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so
(E) like artistic talent or social skill are likely shaped by thousands, if not tens of thousands, of the 80,000 or so

正确答案是A

请问：1）选项B错在哪？   2） 选项A 中 “of the 80,000 or so genes in the human genome” 是什么结构？ 怎么理解呢？