Why are there only two rough er per cell?

What is the purpose of the middle ear? Does chlorophyll make frass green? What is responsible for supplying energy for the cell? What does an enzymes need to bind to in order to be able to catalyze a specific reaction? Explain how high tides and low tides occur? How would a contaminated unknown sample affect the accurate identification of the unknown? What is the main feature of kinetic theory? Name the organs of the respiratory system in order from the mouth to the lungs? Scientists know that the studies they are doing on earthquakes will lead to accurate predictions of earthquakes.? Why did farmers lose their farms during the dust bowl? How many stars are there in each Galaxy? What problems might a plant have if the roots were not spread out? What are examples of kinesiology? Which region contain elements with two valence electrons? What factors make chlorofluorocarbons especially problematic? How can incomplete proteins be made useful to the body? How do the psychological functions of human beings and other complex organisms reflect the basic functions of individual cells? What would an alien from Saturn be called? Is steel wool a mixture- solution? What are the two types of of mixture and give five example each?