Answer: going down a slide.
Justification:
The term passive transport is used to the describe the movement of particles in circumsantaces that do not require the use of energy.
It is mainly used for some physical process related to particles like diffusion or osmosis.
For illustrative purposes. it is compared with the movment of an object down a hill (or a slide as in the case of this question) as the object will go from high to low without requiring the use of energy.
