Birds and humans are theorized to have a common ancestor because they have homologous structures. Which evidence best supports this theory?

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   

Use a magnet to separate iron, evaporate water, i'm not sure how to separate the other two i'm sorry but good luck