From what i can gather it looks like d
Anything that has mass and volume (takes up space) is called matter.
I believe the most appropriate answer would be to change the core from wood to iron. This is because iron is a magnetic material while wood is not magnetic hence cant acquire magnetism. Other factors that would increase the strength of electromagnet would be; increasing the amount of electric current, and increasing the number of windings.
Burning charcoal is a chemical reaction called combustion
