If the current president is assassinated, then the vice president will assume the role of president.
Agriculture is a science of cultivating products in different places with various temperatures. The agriculture helps to produce the food that is good for marketing at any place. The agriculture is well known as the art of generating healthy food for people all round the world.
Another way your question could be framed is “why do nations use imperialism on weaker countries?” and the simple answer is there are several motives such as ethnocentric purposes, religion, access to natural resources, expanding power, etc. Specifically people resort to imperialism on weaker countries because they are vulnerable to accept whatever helps the people survive in times of unrest.
