Sneezing, scratchy throat, runny nose -- everyone knows the first miserable signs of a common cold. But what is a common cold really? What causes you to .\r<br>\r<br>Whether you caught the common cold or came down with something much worse, have you ever wondered what is actually going on inside your body?\r<br>\r<br>A weekly show where we endeavor to answer one of your big questions. This week, Jacob White asks, Why does my nose get runny when Im cold? -- Mental .\r<br>\r<br>When you get the flu, viruses turn your cells into tiny factories that help spread the disease. In this animation, NPRs Robert Krulwich and medical animator David .
