DNA is made of two chains of nucleotides. Which type of bonds hold the chains together?
hydrogen bonds
covalent bonds
ionic bonds
polar covalent bonds

Wind energy is plentiful in regions with vast open spaces it is a non polluting renewable resource what could be an economic factor that makes the use of this resource less feasible then non renewable resource even in such regions

What are two reasons for why a species might disappear from the fossil record?

Patient has just received an organ transplant which treatment would be most effective in preventing the patient’s body from