1) What happened around 10,000 years ago that changed the way many humans live?
A. Humans went from being cave dwellers to roaming hunter-gatherers.
B. Humans went from living on farms to working in factories.
C. Humans went from being roaming hunter-gatherers to settled farmers.
D. Humans invented the spear and became hunters.

In a heat engine of 1000 j of heat enters the system and the piston does 500 j of work what is the final internal energy of the system if the inital energy was 2000 j we have to do all of these down here 1)write the equation 2)list out your know variables 3)plug the numbers into the equations 4)solve 5)write your solution statemtn that includes inital energuy and final energuy added