题目选项分析

Recently discovered fossil remains strongly suggest that the Australian egg-laying mammals of today are a branch of the main stem of mammalian evolution rather than a type that developed independently from a common ancestor of mammals more than 220 million years ago.

Recently discovered fossil remains strongly suggest that the Australian egg-laying mammals of today are a branch of the main stem of mammalian evolution rather than a type whose development was independent of a common ancestor of mammals more than 220 million years ago.