a question about grammar

zhaodunhong

一个语法题  
2002,5 paper test. i

39. Due to persistent inbreeding, self-pollinating plants have genetically more uniform than cross-pollinating plants, which harbor more genetic variablility.

The answer is B, but I prefer D.

Need someone to explain it!

Thanks!

beckyfxie

uniform 是作为形容词用的，因为1.用genetically 副词修饰，2.含义不是名词“制服”。

bootcat

那是不是have 改成 are 呢?

mumiu

是的：） uniform is an adj.