Why do red blood cells collect at the bottom of a tube when centrifuged?

What is the name of the disease that results in mucus building up in your chest or lungs? How long does encephalitis last? Which vitamin has been shown to have an important role in wound healing and maintining healthy gums? How long does fainting last? Do i need to hold my PC muscle when musturbating? I have dentures do they have something of a snap on and off denture so you dont have to use that gum gel? How do you get used to a first bra? What are the Fast twitch muscles and slow twitch muscles? What synonyms exist for 'robots'? Is Down Syndrome a birth defect? What does the reflex action involve? Can viruses cause foodborne illness? What type of attack is when you get blurry vision and can't breathe you get dizzy and then the after effect is a headache but its not a panic attack cause im not scared or startled? What happens to the chromosomes when a baby has hydrocephalus? Examples Durkheims idea that deviance can serve positive function? How are high pressure gases stored and industrial use to prevent loss? When you swallow the mucus does it go to your stomach? Can Carvedilol cause memory problems? What meds can be given in the deltoid muscle? What do muscles do during normal activity?