FILL IN THE BLANK: Paleontologists study ancient organisms. Over millions of years, sediment hardens into rock and preserves the remains of living
things. A
is the impression that an organism or part of
an organism leaves in rock.

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

How many moles of lead are in 1.50 x 10^12 atoms of lead? could you explain the answer as well and not just give it to me i am refreshing for finals and i need to know how to do it

What is a substance? a. a physical property of matter b. a chemical property of matter c. an element or compound that cannot be physically separated d. characteristics used to tell the difference between mixtures