1. Oral cavity remains moist due to presence of a fluid known as _______.   Hint First letter clue   2. _______ is the organ of smell.   First letter clue   3. _______ is the opening in the body through which feces are excreted.   First letter clue   4. _______ are the main respiratory organs.   First letter clue   5. _______ are the organs of hearing.   First letter clue   6. Kidneys are the main _______ organs.   First letter clue   7. Food descends from the mouth to the stomach through a muscular tube known as _______.   First letter clue