A、The nuclear transfer B、The process taking DNA C、The normal reproductive process D、The creation of cells C克隆是个热门话题，有关克隆的文章无非谈论

What is cloning? Cloning is the creation of cells or whole animals using DNA from a single "parent", by passing the normal reproductive process. The clone has the same DNA as the parent.
   The most common process takes DNA from one cell and puts it in a hollowed-out egg. Chemicals and electricity are then used to encourage the new DNA to fuse with the egg and develop into an embryo. This technique is called nuclear transfer.
   The first cloned animal in human history is a sheep called Dolly. It is very important because it was the first mammal to be cloned using DNA taken from an adult cell. Previously, animals had only been cloned using embryo cells, which already have the potential to become a complete embryo in its own right. The big breakthrough with Doily was to make a clone from an ordinary, adult cell.
   When it comes to the question of whether cloned animals are normal and healthy, the answer is YES. Doily is, but scientists do not yet know whether this is the exception or the rule. Some early evidence suggests that clones may have health problems and that they may age prematurely.
   With the birth of Dolly, many people are worried that a human clone may be born soon. It’s possible in theory. But the technology of reproductive cloning is still in its very early stages and there is much that scientist do not understand. That’s more, human cloning is already banned by law in the United Kingdom. The former President of the United States Bill Clinton proposed banning research in to producing human clones in the US for five years. Some measures have also been taken to establish international agreements banning live human clones.