I'm assuming you want the first law of thermodynamics.
The First Law of Thermodynamics states that heat is a form of energy and cannot be created or destroyed. It can, however, be transferred from one location to another and can be converted into other forms of energy.
A) 5 kg block of wood
B) 100 kg person
C) 412 kg motorcycle
D) 2540 kg elephant
Answer: D
It's number three on your worksheet. ;)
Then, number of protons would be equal to number of electrons.