1. Deepest part of the ocean   Hint First letter clue   2. Hottest planet of our solar system   First letter clue   3. River with the greatest water flow   First letter clue   4. Heaviest satellite (natural) of our solar system   First letter clue   5. Planet closest to Earth   First letter clue   6. Brightest planet as viewed from the Earth   First letter clue   7. Highest waterfall   First letter clue