Answer:
See explanation
Step-by-step explanation:
The covalent network solid is composed of a network of strong covalent bonds rather than discreet molecules.
Covalent network solids are composed of atoms covalently bonded together into a three-dimensional network or layers of two-dimensional networks. Due to the strength of the covalent bonds, covalent network solids have high melting points(Khan Academy).
Examples of covalent network solids are Boron nitride, Silicon dioxide, diamond, graphite etc.