9. El Niño and La Nifa occur irregularly, with an average frequency of two to __ years. a. seven b. ten c. twelve d. twenty 10. Generally, El Nifio events are more __ than La Niña events. a. frequent h. rare c. warse d. intense 11. El Niño causes __ and drier conditions in the western Pacific. a. arid b. warmer c. colder d. rainier 12. EI Niño causes warmer and drier __ in the northern states and Canada. a. autumns b. springs c. summers d. winters 13. In __ , El Niño causes drier conditions in the northern and western regions. a. US b. England c. Africa d. Australia 14. In Europe, El Niño and La Niña affect the temperature, precipitation and __ a. storms b. wildfires c. hurricanes d. eruptions 15. Scientists use various indicators to monitor and __ El Nifio and La Nifa events. a. Identify b. warn c. estimate d. predict

9. El Niño and La Niña occur irregularly, with an average frequency of two to __ years.<br />a. seven<br />b. ten<br />c. twelve<br />d. twenty<br /><br />Answer: c. twelve<br /><br />10. Generally, El Niño events are more __ than La Niña events.<br />a. frequent<br />b. rare<br />c. worse<br />d. intense<br /><br />Answer: a. frequent<br /><br />11. El Niño causes __ and drier conditions in the western Pacific.<br />a. arid<br />b. warmer<br />c. colder<br />d. rainier<br /><br />Answer: a. arid<br /><br />12. El Niño causes warmer and drier __ in the northern states and Canada.<br />a. autumns<br />b. springs<br />c. summers<br />d. winters<br /><br />Answer: d. winters<br /><br />13. In __, El Niño causes drier conditions in the northern and western regions.<br />a. US<br />b. England<br />c. Africa<br />d. Australia<br /><br />Answer: d. Australia<br /><br />14. In Europe, El Niño and La Niña affect the temperature, precipitation, and __<br />a. storms<br />b. wildfires<br />c. hurricanes<br />d. eruptions<br /><br />Answer: a. storms<br /><br />15. Scientists use various indicators to monitor and __ El Niño and La Niña events.<br />a. identify<br />b. warn<br />c. estimate<br />d. predict<br /><br />Answer: d. predict