Here's why:
* Fluidity: Fluids, like water and air, can flow and change shape easily. This means they offer relatively low resistance to objects moving through them.
* Low Viscosity: Viscosity refers to a fluid's resistance to flow. Water and air have relatively low viscosities compared to other substances like honey or molasses. This allows objects to move through them with less friction.
* Compressibility: Air is compressible, meaning its density can change under pressure. This allows for smoother movement of objects, as the air can move around them rather than creating significant resistance.
In contrast:
* Solids: Solids have a fixed shape and offer high resistance to movement due to their tightly packed molecules.
Therefore, the fluidity of water and air makes them suitable mediums for motion, allowing objects to move through them with less effort and resistance.
