What was the problem with using valves in computars?

Which mineral is an essential part of more than 100 enzyme and is involved in digestion? What happens if you breathe glitter? What are some of the early warnings of a stroke? Why are ECG and pulse rates similar? Can you eat porridge with gallstones? How do you know if you have cancer cells in your body? Does Smooth muscles activity generates heat to help maintain body temperature? The ultimate end product of protein digestion is called? Does terbinafine affect teeth? What happens to your arteries when drinking alcohol? What causes primary hyperparathyroidism? Where were Lucy's bones found? How is Huntington's disease different form Alzheimer's disease? What style of painting is known for its use of dramatic effects to arouse emotions? What is damage to the skin and underlying tissues caused by prolonged exposure to extreme cold is called? Abbreviations is a test for HIV-AIDS? What does it mean when your skin itch a lot? How is sex determined in humans? What are symptoms of cerebral dysrhythmia? What system is the spinal cord part of?