Kurt Benirschke, a researcher at the University of California San Diego 【小题1】 (start) collecting skin samples from rare and 【小题2】 (danger) animals in 1972. A few years later, he moved his collection to San Diego Zoo, and called it the Frozen Zoo. Today, the Frozen Zoo is 【小题3】 world’s largest animal cryobank, with samples 【小题4】 over 10,500 individual animals from 1,220 species. Since the Frozen Zoo was founded, many milestones 【小题5】 (reach) in the field of genetics, starting with the cloning of the first animal — a sheep 【小题6】 (name) Dolly — in 1996. Starting in 2001, four endangered species have been cloned using genetic material from the Frozen Zoo. 【小题7】 cloning isn’t perfect, it’s a useful tool to help save endangered species, because it can increase genetic 【小题8】 (diverse). When the population of a species decline, the remaining animals are forced to inbreed and the genetic pool shrinks, further 【小题9】 (threaten) survival. In a species of animals, the genetic diversity is 【小题10】 gives it its resilience.

Today, giant pandas are considered to be one of the world’s best-known animals. People make huge efforts 【小题1】 (protect) them and luckily their efforts are paying off in some areas. 【小题2】 (global) recognized as a leading symbol of both China and nature conservation in general, giant pandas are popular in the world. But global interest in the animal only 【小题3】 (take) off in the 20th century.

The inspiration for WWF’s logo (标识) came from Chi Chi, 【小题4】 giant panda that arrived at London Zoo in 1958. Being aware of the need for a remarkable symbol to break through all language barriers, one of the WWF’s 【小题5】 (founder) agreed to make the big furry panda with her distinctive black and white coat a great logo. The first pieces 【小题6】 were done by the British environmentalist and artist Gerald Watterson became modestly successful. Later, 【小题7】 (base) on these drafts, Sir Peter Scott, drew the first logo. He said at the time, “we want an animal that is beautiful and endangered, and is loved for its 【小题8】 (attract) qualities. We also want an animal that is black and white to cut printing costs. To our relief, we make 【小题9】 eventually.”

The panda has ever since become a symbol not just for WWF, 【小题10】 for the conservation movement as well.

For the Stone Age people, 【小题1】 (hunt) was an important way to get food. Stone Age hunter had only crude weapons 【小题2】 (make) of stone and wood. When they went hunting, their weapons were not powerful enough 【小题3】 (kill) big animals so they had to rely more upon their wisdom than weapons.   Stone Age hunters often cooperated with each other in hunting big animals. Some hunters drove a herd of animals like horses or buffaloes over steep cliffs, and 【小题4】 waited at the bottom of the cliffs to finish 【小题5】 kill. Another popular method was to dig a deep pit. The pit then was covered with branches and dirt. 【小题6】 an animal walked over the pit, it fell in and was trapped. The hunters rolled heavy stones on the animal and killed it.

Modern hunters are equipped 【小题7】 powerful weapons, but for most of them, hunting is more for pleasure than for food. Because many big animals like lions, tigers and elephants are decreasing in number rapidly, they 【小题8】 no longer be hunted at will. Nowadays in many countries, hunting 【小题9】(prohibit) in national environments. And even in some countries 【小题10】 hunting is permitted, a hunter has to get a license for hunting particular game in a particular season; otherwise he will be punished as poacher.