In mathematics and computer science, graph theory is the study of graphs, mathematical
structures used to model pairwise relations between objects from a certain collection. A
graph in this context is a collection of vertices or nodes and a collection of edges that
connect pairs of vertices. An edge may be undirected, meaning that there is no distinction
between the two vertices associated with it, or directed, in which it is directed from one
vertex to another. The graph, in addition to vertices, may contain only undirected edges
or only directed edges or a combination of both. The graphs studied in graph theory
should not be confused with the graphs of functions or other kinds of graphs.
Graphs can be used in modelling and treatment of many problems of practical inter-
est in physical, biological and social systems. In computer science, graphs are used to
represent networks of communication, data organization, computational devices, flow of
computation, etc. In chemistry a graph makes a natural model for a molecule, where
vertices represent atoms and edges represent bonds. This approach is especially used in
computer processing of molecular structures. Likewise, graph theory is useful in conser-
vation biology where a vertex can represent regions where certain species exist and the
edges represent migration paths, or movement between the regions. This information is
important when looking at breeding patterns or tracking the spread of diseases or how
changes in the movement of one species can affect the other species.Among the following statements, the false statement is
(A) In a study of interacting particles, mutual forces can be taken as edges.
(B) In a study of a bus network, zonal boundaries can be taken as edges.
(C) In the nervous system, sensory receptors can be taken as vertices.
(D) In a study of government aid programme, aid recipients can be taken as ver-
tices.