Which is a gas commonly found in smog?

Which action is characterized of mental illness 1.brushing teeth every hour because ones mouth feels dirty ? 2. forgetting to eat breakfast on a busy day? 3.crying three days over a relationship breakup? 4.feeling embarrassed about going to school after failing in front of friends?

Absorption of food occurs in the small intestines true or false

Can someone give me a hand with this one.