Small pieces of carbon, granules and each one has significant amounts of surface area that allow for particles and organic matter to absorb onto each one of these granules.
Give a little piece of the virus, also known as antigen, to someone not enough to make them sick and their body will be taught to make antibodies to it.
In 2016, a small piece of debris cracked a window on the orbiting outpost and in December its crew prepared for an emergency evacuation after a Russian anti-satellite missile test created a massive debris cloud.