Which of the following was a key in the growth of the empire of axum?

a. theta waves. this is because the person is in a light sleep which means the brain waves would show these kind of waves.

most people now work in jobs where they do one  kind  of work; they are carpenters, bankers, cooks, mechanics, and so forth. likewise, most  businesses produce  only certainkinds  of  goods  or  services, such as cars, tacos, or gardening  services. this feature of  production  is known as specialization.