it is an organ. the main organ in the body. I wish your question was a little more clear, like multiple choice would be very helpful to what my choices are.
Between a cation, which is usually a metal, and an anion, which is usually a nonmetal. A covalent bond involves a pair of electrons being shared between atoms.
Oxygen,carbon,nitrogen and hydrogen hope this helps
Using statistics.
Make a tree diagram - probability adds up to 1
