请教prep模考ir部分的一道逻辑题

ding22113344

就想问一下，这个为什么不能support？
Swamp sparrows live in a variety of wetland habitats. Unlike most swamp sparrows, which live in freshwater habitat, the coastal-plain subspecies lives in tidal wetlands, where freshwater and seawater mix and the mud is gray rather than brown. Coastal-plain swamp sparrows differ form all other popilations of swamp sparrows in having plumage that is gray brown rather than rusty brown. DNA a nlysis indicates several imprtant genetic differences between swamp sparrows that inhabit itdal marshes and other subspecies of swamp sparrows. Therefore there must have been genetic-selection pressure on swamp sparrows in tidal marshes to become darker and grayer.
我想问一下：Some species of birds that live in tidal marshed do not have gray plumage.为什么不能加强
答案是这个: Baby birds of the coastal-plain subspecies and baby birds of a freshwater swamp subspecies, all raised on an identical diet under controlled conditions, grew plumage similar in color to that of their respective parents.

海底风景

some species of birds 这个词定义的范围太广，都不是sparrow了，所以是irrelevant的选项。hope this helps you~