Answer: The type of reproductive barrier represented above is MECHANICAL ISOLATION. The correct option is 1.
Step-by-step explanation:
Isolation in biology is described as a process by which two species are prevented from copulating( interbreeding) which could lead to production of a hybrid offspring. There are five types of isolation which includes:
- ecological
- temporal
- behavioural
- geographical and
- mechanical isolation.
In mechanical isolation, it occurs due to structural carried that keep species isolated from one another. From the example given in the question, the flowering plant species in which one has a deep flower tube and the other has a short narrow flower tube. The plant with a deep flower doesn't have a correct shape (structural barrier) for the pollinator ( honey bee( therefore won't receive a pollen transfer by it. Likewise the short narrow flower tube plant, doesn't have a correct shape for the pollinator( bumblebee) and therefore won't receive a pollen transfer. I hope this helps, thanks.