PLEASE HELP ASAP
Earth's crust is .

an average of 50 miles thick
thickest under the oceans
made of one large plate
made mostly of igneous rock

I believe it's an average of 50 miles thick

Explanation:

did research and the earth is actually thinnest under the ocean and isn't a single plate. It's also made up of mainly oxygen, silicon, aluminum, iron, calcium, sodium, potassium and magnesium, which aren't igneous rocks I believe

im pretty sure its b

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.