Three possible reasons for the expansion of smaller kingdoms are?

over crowding ,spread of disease , or  the need to extend there border to more resouces.

1 -  the possibility to expand the territories

2 - the need to supply the population with food and other resources

3 - spread influence

Explanation:

All kingdoms begin small, and to become big and strong they usually had these arguments to expand their territories.

most people were factory or company owners.

c. troops marched forward in close formation against newer, more accurate weapons