Read the passage and choose the best answer:
Within the last century the amount of carbon dioxide in the atmosphere (26)_______dramatically, largely (27)_______people burn vast amounts of fossil fuels, coal and petroleum and its derivatives. Average global temperature also has increased - by about 0.6 Celsius degree within (28)_______ past century.
Atmospheric scientists (29)_______found that at least half of that temperature increase (30)_______attributed to human activity. They predict that (31)_______dramatic action is taken, global temperature will continue (32)_______by between 1o C and 3.5o C (between 1.8° and 6.3° F) over the next century. Although (33)_______increase may not seem like a great difference, during The Last Ice Age the global temperature (34)_______only 2.2 Celsius degrees cooler than it (35)_______presently.
Trả lời câu hỏi dưới đây:
______(30)