Answer:
Well based on the fact that the very first patented rock crushing machine was made in the year 1830, and the first successful, Eli Whitney Blake's, was in 1858, I'd say the development process was around 30 years.
Answer: We grew lots of crops like peas, beans, and wheat. We also herded animals like goats and oxen or cows.
What was the question? I didn’t quite understand
https://www.quora.com/What-gifted-musician-was-heavily-involved-in-the-1960s-Civil-Rights-Movement-with-Martin-Luther-King-and-Caeser-Chavez try this link, someone asked the question here
