Global warming ______

V. Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions

Global warming is the phenomenon that the average temperature of the earth raises continuously. Its temperatures may rise by 1.4 to 5.8 degrees Celsius. The greenhouse gases such as carbon dioxide or methane are the cause of the global warming. The greenhouse gases create a natural greenhouse effect.

Human activities such as burning fuels, lumbering, and agriculture will release greenhouse gases. Some of the non-human causes are volcanic emissions, solar activity, variations in the earth’s orbit.

What are the effects of global warming? The rising temperature of the earth will cause the polar ice to melt. As the ice melts, the water will cause the rising sea level and pattern of climate changes. The extreme weather such as hurricanes, tornados, droughts, heat wave, and floods occur more frequently. Other effects of global warming are lower agricultural productions, animal extinctions, or reduced summer stream flows.

There are still many scientific uncertainties of causes and effects of global warming. Some scientists argue that, “Even if there are no greenhouse gases, the events of rising sea and global warming would continue. The carbon dioxide is known for its long average atmospheric lifetime”.

Global warming ______

• A. makes the earth cooler and cooler
• B. makes the temperature of the earth increase
• C. is not caused by carbon dioxide
• D. has no relation to the greenhouse gases