I believe the answer is exhaust from automobiles
Serotonin which is an abnormal chemical activity in the body's endocrine system.
Answer: <em>Toast</em>
Explanation:
A toast can be described as a type of a brief speech made in order to congratulate, appreciate and remember an individual or his/her contribution. It is also referred to as a ritual where one may express goodwill or honor to an individual, institution, group or event. The tone through which it is conveyed is mostly humorous or solemn.
