<span>All cells have the same DNA. They are different because different genes have been locked up and only some of them are expressed. The process began in the embryonic stage, when stem cells are turned into different types of cells by turning off some of the genes. Scientists have been looking for ways to reverse the process, meaning turning specialized cells back into stem cells. Some success has been reported using different methods. The latest one uses a weak acid to stress the cells.</span>
It would be C, The internal structure of cells withing the body. Microscopes are designed to look at cells, as the magnification is at that level.
Skeletal muscle is under voluntary control