Already answered in pm ;P
The answer is the nasal cavity. It is a large air filled space above and behind the nose in the middle of the face, it is lined with hairs and mucus membrane. The function of the nasal cavity is to warm, moisturize, and filter air entering the body before it reaches the lungs.
I'm not entirely sure if I'm correct with this, but I'll try...
Adolescence has to do something with mentality, or how the brain works. It occurs from things like family issues, depression, anxiety, substance abuse, (substance: drugs) sexual abuse, violence, things like that. Men are more likely to suffer from it (I think).
Welp, I've thrown in my two cents, sorry if It's incorrect, at least I tried, lol.
The predators will feed on the prey lowering their birthrates, but while feeding on the prey, the predators' growth rate will lower since there is less prey to feed on.