Identify the true statements about viscosity. Check All That Apply Viscosity occurs due to the internal frictional force that develops between different layers of fluids as they are forced to move relative to each other. Viscosity occurs due to the internal frictional force that develops between different layers of fluids as they are forced to move relative to each other. Viscosity is caused by the cohesive forces between the molecules in liquids, and by the molecular collisions in gases. Viscosity is caused by the cohesive forces between the molecules in liquids, and by the molecular collisions in gases. Viscosity occurs due to the external force that is applied between different layers of fluids as they move relative to each other. Viscosity occurs due to the external force that is applied between different layers of fluids as they move relative to each other. Viscosity is caused by the molecular collisions in liquids, and by adhesive forces between the molecules in gases. Viscosity is caused by the molecular collisions in liquids, and by adhesive forces between the molecules in gases.