Which of the following are always the same for atoms of the same element?

Asking questions when something is unclear is part of?

Jerrold has to buy 12 copies of a textbook which costs $36.25 per copy. how much must he spend for them?

Saul reaches out to grab a pot of boiling water and something in his body sends a sensation to his brain to warn him of the heat coming from the handle. what organ is responsible for protecting saul from the heat?