Who authored the article? Is this person a scientist or an expert in chemistry?
What is the purpose of the article?
Does the article state facts that scientists can prove with evidence?
Are there opinions in the article?
How old is the article?
Do other credible sources support the statements in this article?
Find some credible websites, and note the information they contain. Write down two or three sources that you’ll use for your presentation, and cite them using MLA (Modern Language Association) citation methods. Write one or two sentences stating how the source will help you answer the questions from part A.

personal, she chose to do it.

the answer to this question is 3.

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.