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.
What is the structure of NaCl? The difference between an ionic bond and a covalent bond is that the former requires an electron acceptor and an electron donor. In a covalent bond, the atoms are equally attracted to each other because of their shared electronegativity.