Would it have been better if prometheus never came and gave the people fire? was humanity better off because it had fire and civilization, or worse off because the cost was misery and disease?

According to the myth, Prometheus gave the people fire against the wishes of the gods. The gods, in retaliation, punished the people by sending them misery and disease. It is difficult to say whether this was a convenient bargain. However, it most likely was, as fire allowed people to be warm and cook food, thus fulfilling some of the most basic needs of human beings.

the answer to your question is a. the salt plains

in 1811, he led an expedition, known as the george c. sibley expedition, to improve relations with the pawnee and kansa tribes, and also to locate the rumored jefferson's salt mountain

um how much