Read the statements

• climate change eliminated old food supplies.
• the population grew and there was a need for more food.
• societies were growing more complex.
• new tools made food production, collection, and storage easier.

which best describes the statements related to the origins of humans?

a) they are causes of the neolithic revolution.
b) they are results of migration from africa.
c) they are reasons why people stopped moving.
d) they are characteristics of new civilizations.