Over the next 20 to 50 years, it will become...

Câu hỏi: Over the next 20 to 50 years, it will become harder to tell the (1) _____ between the human and the machine. All, body (2) will be replaceable. Computers will function like the human brain with the ability to recognize feelings and respond in a feeling way. They will then produce fake people. We will then be able to create a machine duplicate of ourselves so we will appear to be alive long after we are dead. Maybe a few decades later, a way will be found to transfer our spirit, including our (2) _____ and thoughts, to the new body. Then we can choose to live for as long as we want. It might be expensive. When it becomes possible to do a spirit transfer, they will figure out (3) _____ to do them automatically. So we will be able to reside within whichever duplicate we want, whenever we want. 

A. difference

B. change

C. variety

D. appearance