Quick question!! Is a complex sentence in writing subject or reading or history subject!? Havent done it in forever im 14!

2686-2181 bce-- "egyptian civilization developed along the nile river in large part because the river’s annual flooding ensured reliable, rich soil for growing crops."

1069-664 bce-- "ancient egyptians developed wide-reaching trade networks along the nile, in the red sea, and in the near east."

i think it’s a i hope that right : )