1. Food descends from the mouth to the stomach through a muscular tube known as _______.   Hint First letter clue   2. Kidneys are the main _______ organs.   First letter clue   3. Salivary glands secrete a fluid known as _______ which helps in digestion as well as in swallowing of food.   First letter clue   4. _______ is a tubular structure through which urine is excreted out of the body.   First letter clue   5. Heart is divided into _______ chambers.   First letter clue   6. _______ is a sac-like structure which stores urine.   First letter clue   7. Complex food particles are broken into simple food particles through the process of _______.   First letter clue