Viruses reproduce [blank_start]rapidly[blank_end] inside the body. They go into your cells and use the cell's [blank_start]organelles[blank_end] to [blank_start]replicate[blank_end] themselves. Eventually, the cell will [blank_start]burst[blank_end], releasing the new viruses into your body, the cell bursting is what makes you feel [blank_start]ill[blank_end].