investigate whether table salt can readily dissolve in water as it does in cooking oil and methylated spirit in room temperature​

The answer should be c.

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf   

Yeah, but what are you trying to ask?

Contained in chromosomes which are located in the nucleus of the cell.