Answer:
The stem cells was discovered by Ernest McCulloch and James Till in 1981. Studies conducted for stem cells can be used for bone marrow transplantation and to treat various diseases.
Explanation:
Stem cell are the cells that has the ability to differentiate into different cells of the body. In 1978 human cord blood discovered as stem cell. The stem cell research come to known in 1981.
Ernest McCulloch and James Till discovered the stem cell research while working on the mice bone marrow. He found that the different blood cells were formed by the single class of cells.
Experiments on mice and other animals have been conducted to study the stem cells so far. The study of stem cell is useful to cure the genetic defects, Cancer and other harmful diseases.
parental genotype I^o I^a × I^o I^b
Geographic isolation of a group of organisms eventually stops gene flow from other groups of same species. Thus isolated group evolves by accumulating new mutations not to be found in members of related groups.
You're right, it is D.
A theory can be changed if evidence is found that contradicts the current theory.
Is there a question i’m supposed to answer or is it just completely free?
