Which of the following statements are true?
a. energy as heat flows from a lower temperature to a higher temperature
b. energy as heat flows from a higher temperature to a lower temperature
c. the amount of het in a closed system is constant
d. energy as heat flowing into an object is determined by the amount of work done on the object.

i know the answer is not c.

Aballoon is rising vertically upwards at a velocity of 10m/s. when it is at a height of 45m from the ground, a parachute bails out from it. after 3s he opens his parachute and decelerates ata a constant rate 5m/s. when. (a) what was the height of the parachutist above the ground when he opened his parachute? (b)how far is the parachutist from the balloon at t=3s? (c)with what velocity does the parachutist hit the ground? (d)after how long does the parachutist hit the ground after his exist from the balloon?