Mysterious ridge and two holes

In many animals, including primates, the input devices responsible for sight, hearing, smell, and taste are facing forward. However, only humans have their olfactory organs raised like Mt. Fuji, and the holes are direct for downward. Moreover, there are two nose holes. We can determine the position of the object by having two eyes and ears. However, the nostrils become one on the inside. To date, I’m not happy to know no clear reason for this.