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綜合寫作

The giant panda Is a species of bear native to south central China.It has become a rare species; there are fears that it may become extinct in the future. While scientists are undertaking many intense efforts to save panda populations,some of the pandas characteristics pose a serious challenge to its survival.

First, pandas have digestive systems(organs that convert food into energy and nutrients) that are not well adapted for their plant based diets. Pandas originally evolved from bears that fed on both meat and plants. While pandas diet currently consists only of plants their digestive system is still better suited for digesting meat.In the end,pandas manage to successfully digest only about 17 percent of all the plants they eat.Their poor digestive efficiency increases pandas risk of becoming extinct.

Second,pandas experience serious problems with breeding- mating and having offspring.In the wild, female pandas are receptive to breeding for only a few days a year, which seriously limits opportunities for pandas to reproduce naturally Breeding pandas in captivity (in Zoos,for example)is complicated by pandas behavior captive pandas are often indifferent to mates even during the breeding season or are unsuccessful when attempting to breed. Because of these issues, zoos that keep pandas usually resort to artificial breeding techniques;unfortunately,such techniques are also not very effective.

Finally, food shortage is a serious obstacle to the pandas survival.In general,pandas feed almost exclusively on a plant called bamboo.The problem is that bamboo populations naturally go through periodic cycles: after a period of growth, the plants flower and die.It can take years before the bamboo population grows back again. Because of the panda’s heavy reliance on bamboo for food, the period of bamboo shortage between die-off and regrowth poses a significant threat to wild pandas.