Which statement best summarize the relationship between the muscular system and the cardiovascular system? a. the heart is protected from injury by the breastbone. b. nutrients are carried to the heart through arteries and veins c. messages are carried by nerves between the brain and the heart. d. the heart contract and expands as it pumps blood through the body and how do i explain that i know the

what is the question?

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.