A relative of a friend of yours had a spinal cord injury after a bad car accident. The medical team has decided that this patient is a good candidate for a clinical trial using stem cell therapy. Your friend has not had a biology course since high school, so you are going to write for him or her a two-page discussion of stem cell information. In your discussion, include a description of the biology of stem cells, and explain how these cells are unique in their ability to treat diseases and injury.