Zachary wants to model a landform that changed due to earthquakes and wind erosion. Which model is most appropriate for him to use?
an illustratic showing the original appearance of the landform
a diagram showing cracks in the Earth from an earthquake
an oversimplified diagram depicting the cause of the earthquake
an illustration including only the contribution of wind erosion to the landform change

i'm assuming that the correct answer is indeed the first one/ "a"..

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.