The given question is incomplete. The complete question is:
All of the flower mechanisms would help prevent pollination by a foreign species except __________.
A. A pollen tube grows in the style of its own species.
B. The stigma is sticky mainly to its own species of pollen.
C. The timing of flowering keeps pollinators moving among a limited number of species.
D. Flowers attract a small number of specialized pollinators, and therefore pollen is not spread equally to all available species of flowers.
E. Flowers of different species are the same color and attract similar pollinators.
Answer:
E. Flowers of different species are the same color and attract similar pollinators.
Step-by-step explanation:
Plants of different species develop various morphological, physiological and behavioral strategies to ensure that the flowers of one species are not pollinated by pollens from any other species. One such structural adaptation is the production of flowers of a different color, size and shape.
These structural distinctions allow specific pollinators to visit the flowers of the particular species only. It ensures pollens from a different plant species do not land on the flowers of some other species. Production of flowers of the same color by different plant species would attract same pollinators and may result in pollination by a foreign species.