Respuesta :
Answer: 1. a video that shows a large river that has penguin populations on both sides.
Explanation:
Reproductive isolation is a phenomena which occurs when members of the same species becomes separated due to a geographical, physical or behavioral barrier. The members of the same species after separation adapt to changes and this is the basis of speciation or development of new species.
Option 1 is the correct option as the river is the geographical barrier, between the two separated penguin populations.