[问答题]
1.Describe the method jq3 imq59 0hpdkn07li /anq9vs ree53used by scientists to deduce carbon dioxide concentrations from thousan/a5q3sn 0lk7 i nev9erds of years ago.
2.Explain why rising levels of atmospheric carbon dioxide are the main cause of climate change.
3.How have increased carbon dioxide levels affected reef-building corals in marine waters?