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.
In this type of solids the constituent particles are atoms of the same or different elements connected to each other by covalent bond. So a network of covalent bonds is formed throughout the crystal and they form a giant molecule. The most common example is diamond, silicon carbide (SiC) and graphite, etc.