Why does Stephen Hawking have a hole in his thoat?

What are two continents whose edges are not all on plate boundaries? Which biochemical cycle is least dependent on biotic processes? What are nonliving things found in an ecosystem? What is the depends to some extent on temperature? What is the urine part of the woman vegerina called? What would stop at plant from growing? Scientists study rocks using what important criteria? How do the rocks in the mantle move? How many atoms are present in 16 g of o and 8 g of s? What two planets does the asteroid belt come in between? Why do acid fast cells not show the color of the blue dye? What would cause a 20A circuit breaker to remain on but have power with only two outlets and nothing anywhere else? Why is a rain gauge important to farmers? Did anyone die in the Christchurch earthquake? What benefit you derive in studying biology? Is disinfectant dangerous? If 55 percent of a group have brown hair and 80 percent of the same group do not have red hair what fraction of those who do not have brown hair have red hair? How do you change km to mi? How do you determine the transcription start site? Why does white out burn your skin?