Read the article below and decide which answer best fits each space. Đọc đoạn văn dưới và chọn từ thích hợp cho mỗi chỗ trống.


Every year about seventeen million animals are used in the laboratory ___(1)___. But in many countries today, a difficult question is being asked: Do we have the right to use animals this way? The case for using animals in research: The use of animals in medical research has many practical ___(2)___. Animal research has enabled researchers to develop ___(3)___ for many diseases, such as heart disease and depression. It would not have been possible to develop vaccines for diseases like smallpox and polio without animal research. Every drug anyone takes today was ___(4)___ first on animals. Future medical research is ___(5)___ on the use of animals. Which is more important: the life of a rat or that of a three-year-old child? Medical research is also a(n) ___(6)___ way of using unwanted animals. Last year, over twelve million animals had to be killed in animal shelters because nobody wanted them as pets. The case against using animals in research: The fact that humans benefit cannot be used to justify experimenting of other humans. Animals ___(7)___ a lot during these experiments. They are ___(8)___ to live in small cages, and they may be unable to move. Much of the research that is ___(9)___ out is unnecessary anyway. Animals have the same ___(10)___ as human to do be able to move freely and not to have pain or fear forced on them. Researchers must find other ways of doing their research, using cells culture and computer modeling. There should be no animals in research laboratories at all.