In a hypothetical organism structure X develops after struct

In a hypothetical organism, structure X develops after structures A, B, and C. Biologists interested in the development of structure X remove various combinations of structures A, B, and C. Removal of structure A does not affect development of X. Removal of structure B prevents development of X. Removal of structure C does not affect development of X. Removal of both structures A and B results in X not developing.
Based on these results, we can infer that the structure(s) ______ most likely supply inducers of structure X.

A. A only
B. B only
C. C only
D. A and B
E. A and C

Solution

Answer: B) B Only

Since removal of structure B prevents Development of X and removal of structure A doesnot affect development of X, therefore when both structures A and B are removed, the affect on the development of X would be a result of removal of B only.