Final answer:
Stem-cell research has accomplished breakthroughs in procedures to regrow cartilage and blood vessels, but not yet the generation of new human limbs. Significant progress has been made in therapeutic applications using various types of stem cells, with growing organs in vitro being a future objective.
Step-by-step explanation:
Stem cell research has led to significant breakthroughs in regenerative medicine, involving the repair and regeneration of damaged tissues. Embryonic stem cells, for example, have been used in the development of therapeutic applications. One such advancement is the procedure to regrow cartilage, which has seen some progress.
Similarly, the process to regrow blood vessels using endothelial stem cells has been a focus of medical research. While there have been efforts to utilize stem cells to generate new tissues, the ability to generate new human limbs has not yet been achieved and remains a goal for the future.
Ongoing experiments in using various types of stem cells such as embryonic stem cells, hematopoietic stem cells, and others have shown that stem cell therapy could potentially improve the quality of life and save the lives of people with various diseases. Adult stem cells, for instance, play a role in renewing and repairing body tissues, and the ability to grow organs in vitro from an individual's own cells is being explored to prevent the issues related to transplant rejection.