Question

both el niño and la niña are weather patterns caused by water temperature changes in the pacific ocean near the equator. during an el niño event, surface ocean temperatures are warmer than usual. this results in wetter than average conditions in the southeastern united states, with warmer than average temperatures over the northwestern united states and canada. during a la niña episode, surface ocean temperatures are cooler than average. la niñas climate effects tend to be the opposite of el niños: temperatures are cooler than normal in the northwest, and the southeast experiences warmer than average winter temperatures. la niña is like el niño in that it tends to last about nine to twelve months. on average, the two events happen every two to seven years.

Explanation:

• "Is caused by changes in water temperature": Both El Niño and La Niña are weather patterns caused by water temperature changes in the Pacific Ocean near the equator. So, both should be checked.
• "Happens when ocean temperatures warm": During an El Niño event, surface ocean temperatures are warmer than usual. So, only El Niño should be checked.
• "Causes cooler temperatures in the Northwest": During a La Niña episode, La Niña's climate effects tend to be the opposite of El Niño's: temperatures are cooler than normal in the Northwest. So, only La Niña should be checked.
• "Typically lasts nine to twelve months": La Niña is like El Niño in that it tends to last about nine to twelve months. So, both should be checked.

Answer:

• Is caused by changes in water temperature: El Niño (checked), La Niña (checked)
• Happens when ocean temperatures warm: El Niño (checked), La Niña (not checked)
• Causes cooler temperatures in the Northwest: El Niño (not checked), La Niña (checked)
• Typically lasts nine to twelve months: El Niño (checked), La Niña (checked)