The type of stream valley likely to form in a mountainous area is a V- shaped valley. This is a narrow valley that has a profile giving the impression of the letter V. This kind of valley is characterized by steeply sloping sides. It results from a stream eroding downward, a process referred to as downcutting. V - shaped valleys form in mountains or highland areas where streams are in their youthful stage and are flowing rapidly down steep slopes.
Because of evolutionary traits based on the environment.
Explanation: This is probably because they live in a similar environment, so they both evolved to have similar adaptations to make them excel in that specific enviroment
