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

• According to the passage, the doers of education are .............

• According to the passage, an exuberant tone of voice may be an indication of a person’s ............

• What is the main topic of the passage?

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• The expression “readministration” in this passage refers to ................

• Which of the following statements can best summarize the main idea of the passage?

• Which of the following can be inferred from the first paragraph?

• The first songs of the Beatles were ............

• Which of the following is true regarding the crust?

• Which of the following statements is not TRUE about Thanksgiving ______?

• What can be said about the mother and son in the passage?

• Many American students have to work part-time throughout their college years because ....................

• How many orchid seeds are typically pollinated at one time?

• It can be inferred from the passage that the countries which are mainly responsible for global warming are ____.

• Based on the passage, what is probably true about the south of France?

• The Asiatic lion ............

• The author states that the reason that infants need to avoid certain foods related to allergies has to do with the infant's ___________ .

• According to the passage, the Railway Mail Service commenced in_________.

• We sometimes think of writing as more real than speech because ..................

• The word “bounds” in line 5 is closest in meaning to ........

• If there was a preceding paragraph to this passage it would most likely be concerned with which of the following topics?