The word "groundbreaking' (Line 3, Para. 5) can be best replaced by______.

A．make efforts to clone the endangered panda
B．save endangered animals from extinction
C．implant embryo into a host animal
D．collect DNA of endangered animals to study

A．Kraemer will work with Chinese scientists in clone researches
B．about two thousand species will probably die out in next few decades
C．Kraemer and his team have succeeded in cloning a dog
D．scientists maintain that cloning animals is worth researching