1. Which characteristic did the early civilizations that developed along the Nile and the Tigris-Euphrates
have in common?
A. Each society's religious beliefs were monotheistic.
B. Cities were built using iron and steel tools.
C. The form of government in each community was based on male voting.
D. Culture and economy were promoted by an agriculture, fertile soil, and natural waterways.

The early river civilzations were the civilzations settled alongside the river. The four early river civilizations included Indus civilizations, Nile civilization, Tigris-Euphrates civilization, and Huang He civilization.

The characteristics that the early civilizations developed along the Nile and the Tigris-Euphrates had in common was the transportation and communication system. Through transportation and communication, the culture and economy of these civilizations were promoted. They were promoted through agriculture, fertile soil, and natural waterways.

Therefore, option D is correct.