Which of the Following Statements Are True of Covalent,hydrogen,or Disulfide

Which of the following statements are true of covalent,hydrogen,or disulfide bonds (Select all that apply) ?

A) Covalent bonds are formed when atoms share electrons.
B) Organic molecules such as glucose are held together by covalent bonds.
C) The element carbon only rarely forms covalent bonds.
D) Hydrogen bonds help maintain the three-dimensional shape of proteins.
E) Disulfide bonds help maintain the three-dimensional shape of carbohydrates.
F) Covalent bonds are relatively strong,except in water,where they weaken and tend to break.