Today I’d like to begin a discussion on the problem of the heating up the earth. First, we’ll touch on the relationship between fluorocarbons and the ozone layer. You probably remember that the ozone layer is the protective shield around the earth. It is important to all life, because it filters out harmful ultraviolet light from the sun. Ozone itself, a form of oxygen, is regularly made by the action of the sun in the upper atmosphere. It is also regularly destroyed by natural chemical processes.

The problem now is that too much of the ozone layer is being destroyed. Scientists suspect that certain chemicals, such as fluorocarbons, are contributing to the depletion of the ozone layer. And how do we use fluorocarbons? The most common uses are in spray cans and cooling systems. The chemical pollution from these fluorocarbons can account for some of the ozone losses that have been reported. There are, however, new studies linking the sun itself to the depletion of the ozone layer. We’ll go into that new study more next time.

What is the most important purpose of the ozone layer?

Câu hỏi liên quan

• The word "hyperactive" is closest in meaning to _____.

• The author’s purpose of writing this passage is to_______.

• The author mentions all of the following as concerns of telecommuting, EXCEPT ...........

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• The word “rude” in paragraph 1 could be best replaced by .................

• The article is mainly about .............

• Most people are afraid of being operated on ............

• According to the author, M.L. ...............

• Based on the information in paragraph 3, which of the following best describes the main difference between parks and rooftop gardens?

• Approximately when did English begin to be used beyond England?

• In paragraph 2, non-native species are mentioned as ______.

• The word “them” in the second paragraph refers to ................

• According to the passage, one benefit of diagrams is ...............

• Which of the following is NOT discussed as an ability animals are thought to have?

• The adaptation process described in the article was completed……

• The word "fused" in line 2 is closest in meaning to .......

• Sign language is said to be very picturesque and exact and can be used internationally EXCEPT for____________

• The best way to protect children from improper material is .............

• The word “all-inclusive” in the passage mostly means .............

• The word “they” in paragraph 4 refers to ...........

• The paragraph following the passage most likely discusses: