Note that there are now several types of treatments and medical providers for which Medicare Part B pays 100% of the approved charges rather than the usual 80%. These categories of care include home health care, clinical laboratory services, and flu and pneumonia vaccines.
A giant covalent structure is a three dimensional structure of atoms held together (obviously) by Covalent bonds. These atoms are often all the same-so the elements Silicon and Carbon in the allotropes Diamond and Graphite are Giant Covalent structures.
Unlike ionic bonding, covalent bonding may have single, double bonds or triple bonds between two atoms. These bonds are formed in such a way that the two atoms obey the octet rule. The bond occurs via the overlapping of atomic orbitals. A single bond is formed when two electrons are shared. A double bond is formed when four electrons are shared. Sharing of six electrons may result in a triple bond. The characteristics of compounds with covalent bonds include strong bonding between two atoms due to similar electronegativity values.