Read the passage from a text about the rain forests of South America. The Importance of Rain Forests

Rain forests clean the air by producing oxygen. Some rainforest plants have healing properties and can be used as medicine. Rain forests are also known to affect the water cycle and weather. The threat of deforestation, however, means these important rain forests may disappear.

Which keywords would students most likely want to include in their notes?

rain forests, deforestation, water cycle
rain forests, however, disappear
weather, used, plants
plants, affect, threat