Plz help! Brainliest if correct! Lots of points!

What is the subscript for oxygen in its molecular formula

How does the presence of oxygen affect the chemical pathways used to extract energy from glucose?

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