Inveterbrate would be a grasshopper
Stem cells are undifferentiated cells that could develop to perform a variety of tasks. One type of stem cell is the embrionic stem cell. There are also adult stem cells. To use embrionic stem cell you need to have fertilized embrios. These can be donated to research. The use of the embrionic stem cells is controversial for this reason.
A control group is a group that does studies or Experiments that does not receive treatment by researchers and is then used as a benchmark to measure how the other tested subjects do. Ex: Experimenting Arizonas and water together.