Seafloor spreading is a phenomenon that occurs at mid-oceanic ridges, such as the mid-atlantic ridge. new crust, which is created by volcanic activity, spreads away from the ridge. seafloor spreading could be one reason a) the continents are drifting apart. b) all earthquakes have their epicenters in oceans. c) most active volcanoes are found in the atlantic ocean. d) the mid-atlantic ridge is the longest mountain range in the world.

catya that's not even a b or c

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.

c. electrical charges of ionic bonds.