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.
Energy comes from making bonds in carbon dioxide and water.
Answer:
the Sun
The Moon gets its light from the Sun. In the same way that the Sun illuminates Earth, the Moon reflects the Sun's light, making it appear bright in our sky.
Answer: Viruses, although not living things, do show some characteristics that they are living. Because they can't reproduce by themselves (without a host), viruses are not considered living. They are made of proteins and glycoproteins like cells are. They contain genetic information needed to produce more viruses in the form of DNA or RNA.
They are acellular, that is, they contain no cytoplasm or cellular organelles. They carry out no metabolism on their own and must replicate using the host cell's metabolic machinery.
