Why did people in other european countries resist napoleon’s efforts to build an empire?

Well, it would mean France would gain power at the expense of other countries. Both because those countries might fall (unwillingly) under French rule or because France might pose a threat to their political sway and power.

The have over 100 billion people in america

The middle? there are 4 pieces. which piece are you talking about? the 2nd or 3rd?