You don’t have to worry about picking the right guy or girl because he /she is already picked for you so it’s less stressful
It is important to have a primary source and a secondary source because it allows you to set up the writing and add information to support or disagree with the topic. If you were reading two books and you were planning on comparing/contrasting them using a specific topic, those two books would be your primary sources. The primary sources are the bulk of the writing while the secondary sources add on in support with your argument. Secondary sources would be source outside of your primary sources (Internet, magazines, newspapers, etc). Primary source is the main source. Secondary source is the source outside of your main source. Secondary sources are usually used to give your paper more factual evidence or things of that source.
The primary purpose of these stage directions (with the gallantry of a young politician) is to indicate a character's tone of voice.
Given that he is referring to the ladies, he has to change the tone of his voice a bit to appeal to them more. He cannot speak in a manly voice which he would normally use while speaking to other men, but rather appear more suave and gentleman-like.
The primary problem is the greenhouse effect. Greenhouse effect is when some gases (including CO2) absorbs some portion of sun's heat to make the atmosphere warm to support life. But when the amount of CO2 etc. increases in the atmosphere, it heats up more than it is required. So, by limiting CO2 emission, we can solve this problem.