Explanation: Path functions: Path functions are defined as the thermodynamical variables which depend on the way/path in which the thermodynamical system achieved the initial and final states. The differential of path functions is inexact. Heat, work and entropy generation are path functions. Point functions: Point functions are defined as the thermodynamic variable which depends on end states only i.e. initial and final states. They do not depend upon the path followed. The differential of point functions is exact. Pressure, temperature, volume, entropy, enthalpy, energy etc are point functions. Similarities between heat and work: Heat and work are both transient phenomena. Systems never possess heat or work, but either or both cross the system boundary when a system undergoes a change of state. Both heat and work are boundary phenomena. Both are observed only at the boundary of the system and both represent the energy crossing the boundary. Both heat and work are path functions and inexact differential equations.