The answer is d
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- You're Welcome.
Moving from the details of Jerrika’s observations to the big picture of rubbing things together to make heat.
Answer:
they could have use some evidence to get this theory.
let's say that the scientist wanted to prove that air didnt exist. you cant see it. that's proof that it maybe doenst exist (of course air exists...I think).
Answer:
They would have more leisure time to themselves.
They would have machines laboring for them.
Explanation:
hope this helps :)