As a historian, using sources would better help understand the past. Using mostly primary sources would better help understand the past as you were there or you get information from someone who was involved in the concept. Before we get into this, a primary source provides firs-handed accounts of an event or time period and are mostly considered very useful and best when explaining a period of time where something great happened. A secondary source describes a summary or discussed information originally presented by another source. That means that the words and what actually happened, could have been altered in a way to best fit the story or change the readers perspective. While using a primary source or secondary source, like a newspaper, it's somewhat difficult to tell which source it is, so you have to trust your gut. Now, as a historian, you would much rather use a primary source since it provides first-hand detail of what happened and what you'd want to share. Overall, it may be said that using a primary source when you're working with something with time, or an event, would be best; rather than a secondary source.
The compound subject is "Young Juan and his father." Both Jaun and his father are the subjects of the sentence, but because there are two of them it means there is a compound subject.
The speed and accleration of a car travelling in reverse and in the normal direction is the same. Therefore the measurement of its speed is still done using the metric system or via miles per hour (mph).
