Which of these is the BEST source of stem cells and minimizes the risk associated with stem cell transplantation?(Please Help!!)

Select one:
a. Stem cells from rejected grafts that initiated an immune response.
b. Stem cells preserved from the umbilical cord of the person.
c. Stem cells from a donor having the same blood group.
d. Stem cells from a donor who is the same age as the patient.

How many cells are our body made of ? ♡

What are some characteristics of a free enterprise economy?

1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area