Extinction, or the dying out of species, is the decrease in the population of a group of animals. There are plenty of causes that can lead to the disappearance of them. This paragraph will show you 3 main causes of extinction. The biggest cause is the polluted environment. Contaminated environments have detrimental effects on both humans and wildlife. It is not difficult to see marine species especially fishes, corals, turtles,... are caught to toxic chemicals such as bottle, nilon, rubbish,... in oceans, rivers and lakes. Beside that, air contamination is also the reason for the reversal of oxygen levels, which threaten numerous of animal’s life. Another result of the dying out of animals is the loss of habitat. Deforestation for harvesting, enlargement of land for farming and the harvesting of wood for fuel and forest products also contribute to comprehensive habitat loss. When habitat is limited, animals may no longer provide the water, food and cover which is essential for their...