The electrons in the outermost shell of the covalent compounds are shared by nearby atoms. As there are no free electrons for conducting electricity, the covalent compounds are perfect insulators at absolute zero. As the temperature increases, some electrons move from valence band to conduction band. This gives rise to conductivity. But as the numbers of charge carriers are very low, covalent compounds are poor conductors. On the other hand metals are good conductors cause of their bonding. Metallic bonding consists of a sea of electrons rather than discreet bonds. The free electrons are able to move freely. Since electricity and heat need electrons to move, the bonding promotes conductivity.
by using rooting harmone roots develop quickly at cutting and and it become more robust than cuttings which don't receive rooting hormone. Cutting harmone is used mostly on ornamental plants in the landscape and to propagate succulents.
It cannot apply on whole plant since it will not mix with old one and a new catergory or plant will develop and it will distroy the originality of the actual plant
