Bonds share electron pairs. ionic metallic hydrogen covalent

Covalent bonds- are bonds that share electron pairs between atoms.

Ionic bonds are bonds that are made after one atom GIVES AWAY one or more electrons to the other atom.

Hydrogen Bonds- bonds between hydrogen(H) and usually O,N, or F. Hydrogen bonds are NOT TRUELY BONDS they are an ELECTROMAGNETIC ATTRACTIONS. These bonds can be Intramolecular(bonds within a molecule) or Intermolecular bonds (between two separate molecules). Individually a hydrogen bond is weak. However, hydrogen bonds can be strong in large numbers.

Metallic Bonding- occurs when metals bond with other metals their valence electrons become "delocalized," or free to move around. This delocalization forms something called the electron sea. In the electron sea, valence electrons DO NOT BELONG TO ANYONE ATOM. 

Therefore, the answer is Covalent bonds.
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Decomposition is the cycle at which bacteria breaks down any organic material into the soil