Explanation: Group 18 is known as the Noble Gases. They are the most stable elements because they have a full outer shell of valence electrons, so they have no need to bond with other elements.
The work done by the elephant to lift one log is the force multiplied by the height at which the log has been lifted: And so, the total work done to lift the 7 logs is 7 times the work done to lift each log:
