Why do your knee hurt when it crack and pop?

What were the long term effects of the cockermouth flood? Type O Blood can only donate to Type O Blood so how are the Type O Blooded people going to ensure their is blood in any Local Blood Bank for them in an emergency? How does the skin work with the circulatory? Will you be allergic to flax seed if allergic to nuts? Should depressed people get pets? Does a narrow urethra cause infertility? What part of the body contains lungs? Is blood corrosive? Which presidents had an STD? What describes the body's recognition of a relatively harmless substance as a dangerous antigen and subsequent mounting of an immune response? How can you get pregnant if on period? Can bone broth cause diarrhea? In hollyoaks who was Melissa played by she was the girl who started hannahs anorexia? How old do you have to be to smoke in the US? Why did mrs.umney faint? How does the large and small muscle development compare to the norms for eight years old? What disease did tsarevich ALEXIE have? Can you play soccer with a blood blister? What affects you in a heart attack? How do you keep a gauge from getting infected?