One of the most significant challenges is building an airplane had to do with "propulsion", since the technology that allowed motors to have enough energy to lift an airplane into the sky with a passenger wasn't available for most of history.
It started a period of violence known as bleeding kansas
Aurelius killed Christians, while Pius was good to his people and kept peace and this was the way Marcus Aurelius and Antoninus Pius differed from each other. The correct option among all the options that are given in the question is the third option. I hope this is the answer you were looking for and it has helped you.
