Cloning is a way of ____(make) an exact copy of another animal and plant____ has two major uses. One is____ gardeners use it to produce commercial quantities of plants. The ____is that it is valuable for research on new species and for medical research on animals. ____, the process of cloning is difficult to undertake.

    Many attempts to clone mammals failed. The first successful clone, Dolly the sheep, made the whole ____(science) world follow its process, though it had ____ problems than the normal sheep. On the other hand, Dolly's appearance ____(raise) a storm of objections and had a great impact ____ the media and public imagination. Different people have different opinions of it. However, scientists still wonder whether cloning will help ____ harm us and where it is leading us.