What was noticed about the shape of coastlines by sailors as early as the sixteenth century? A. The West coastline of North America and East coastline of South America looked like they fit together
B. The East coastline of Asia and West coastline of North American looked like they fit together
C. The West coastline of Africa and East coastline of Australia looked like they fit together
D. The East coastline of South America and West coastline of Africa looked like they fit together

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.