You are presented with the question "What causes heat in a wire?" and the following answer choices: 
- sunlight
 - energy
 - resistance
 - unidirectional
 - kinetic energy
 - photons
 - rays or beams
 - energy barrier

Now knowing that electrical current running through a wire causes that wire to heat up and because of electrical resistance, the passage of electric current through wire produces heat, choose the best answer.


 

   resistance      