Answer:
A. Stone
Explanation:
Bridges of stone or reeds were also constructed to cover distances
Hope this helped ;)
Answer:
Wood is the first likely source. There was no invention to find petroleum, natural gas, or coal
Answer:
Subjects are assigned by chance, rather than by choice, to a group.
Explanation:
In randomization process, the researchers will gather the subjects together and form a group based on that population without even thinking about their characteristics.
This method is often used is the researchers want to make the results of their study to be applicable to heteregonous society with variety of age, genders, ethnicities, and genetic compositon.
Answer: B
in the southern regions of North America
Egypt's fertile soil historically is largely a result of the Nile River and the sediment that the river deposits along its banks during flood seasons and also in its delta year round. This has been changed dramatically since the building of the Aswan Dam.
