Answer:
The amount of data in a multimedia application runs for a few Giga bases and hence storage cost and its processing cost increases. This is one of the disadvantages of using multimedia.
The first one. The commas are correctly placed. Sorry if this is wrong.
"Secondary sources were created by someone who did not experience first-hand or participate in the events or conditions you're researching. For a historical research project, secondary sources are generally scholarly books and articles. A secondary source interprets and analyzes primary sources."
