The Sahara was not always a desert. Geological and archaeological evidence — fossil pollen, ancient lake beds, and rock art depicting crocodiles and giraffes — shows that as recently as 6,000 years ago, the region was a humid grassland. Shifts in Earth's orbital geometry gradually altered monsoon patterns, drying the landscape over millennia.
Which choice best states the main idea of the text?
- Acheck_circle
Multiple lines of evidence show the Sahara was once a humid grassland that dried over millennia.
- B
The Sahara has long been a desert.
- C
Rock art depicts crocodiles and giraffes.
- D
Earth's orbit changes constantly.
Explanation
The passage's main point is the Sahara's transformation, supported by varied evidence — C. A and D are details; B contradicts the text.