The greenhouse effect resulted hundreds of million years ago when _________.
A: the atmosphere changed dramatically
B: oxygen levels on the earth became lower
C: the sea levels became lower greatly
D: the sediment gave off enormous carbon and methane
A: the atmosphere changed dramatically
B: oxygen levels on the earth became lower
C: the sea levels became lower greatly
D: the sediment gave off enormous carbon and methane
举一反三
- Which of the following refers to the retention of the Sun's warmth in the Earth's lower atmosphere by greenhouse gases?
- According to the woman, what happened 200 to 500 million years ago A: Some sea creatures developed vertebrae. B: The first giant squid was captured. C: Some sea creatures shed their shells. D: Sea life became more intelligent.
- The most abundant greenhouse gas in the atmosphere is . A: nitrous oxide B: methane C: chlorofluorocarbons D: carbon dioxide
- The line of authority that extends from upper organizational levels to lower levels, clarifying who reports to whom, is known as the ________.
- According to Maslow's hierarchy of needs, lower levels of needs and higher levels may come into play at the same time.