Directions: The following question consists of a set of four statements. One or more of the statements may have an error of grammar or syntax. Select the statement(s) having the error.

(A) Naturalists continually refer to external conditions, such as climate, food etc., as the only possible causes of variation. (B) Nevertheless, such a conclusion, even if well founded, would be unsatisfactory, until it could be shown how the innumerable species, have to acquire that perfection of structure and coadaptation. (C) It is quite conceivable that a naturalist might come to the conclusion that species have not been independently created, but had descended from other species. (D) Yet it is preposterous to attribute to mere external conditions, the structure of several species.