The last one and I'm pretty sure the second one
One important advantage that primary soruces have over secondary sources is that primary sources offer a firsthand account of an event - b, which isn't the case with secondary sources. Although this leaves primary sources prone to being biased compared to secondary sources.
Answer:
From 3100 BC to 400 BC Ancient Egypt was a successful center of civilization.
Explanation:
Ancient Egypt was a civilization that developed along the middle and lower reaches of the Nile from about 3150 BC until it was conquered by Alexander the Great in 332 BC. It extended south from the Nile estuary to Jebel Barkal near the fourth cataract.
Egyptian civilization depended on the River Nile. When the rains further south caused the river to overtop its banks and cover much of the land, it would immediately irrigate and fertilize the land. This was of great importance in a country where there is virtually no rain.
