How to be prepared in speech un front of class. please help me​

Honestly, there is no need for preparation at all... I have done multiple speeches over multiple audience types and varied audience sizes. All you have to do is understand and remember what you're going to talk about. Understanding is the most important. Furthermore, I urge you to say at the start "I will be attending to any and all queries towards the end of this speech" and you should be able to answer these queries that are thrown at you no matter what it is. Moreover, I highly suggest that you use formal language with your classmate no matter if they're friends or not. Formal language is a must in most speeches

countries such as spain, france and portugal colonized the region. although most of latin america was colonized by spain, the countries of portugal and france also had major influences on the region. due to war and disease, native populations were decimated.