Q1: Practical fluids possess

ANS:D - all the above.

1. Viscosity: Viscosity is the resistance of a fluid to flow. It determines how easily a fluid can deform or move under an applied force. All practical fluids, including liquids and gases, exhibit viscosity to some extent.
2. Surface Tension: Surface tension is the cohesive force that holds the molecules of a liquid together at its surface. It causes liquids to minimize their surface area and form spherical droplets. Surface tension is a characteristic property of liquids.
3. Compressibility: Compressibility refers to the ability of a substance to decrease in volume under pressure. While some fluids, like gases, are highly compressible, others, like liquids, are less compressible but still possess some degree of compressibility.