The passage suggests that the "recent studies" cited in the second paragraph have not done which of the following? A. Made any distinctions between different species of wind-pollinated plants. B. Considered the physical properties of the pollen that is produced by wind-pollinated plants. C. Indicated the general range within which plant-generated airflow disturbances are apt to occur. D. Included investigations of the physics of pollen motion and its relationship to the efficient capture of pollen by the female reproductive organs of wind-pollinated plants. E. Demonstrated that the morphological attributes of the female reproductive organs of wind-pollinated plants are usually evolutionary adaptations to wind pollination.