Final answer:
When no cell energy is required for transport, it is known as passive transport, where substances diffuse across the membrane following the concentration gradient without the use of ATP.
Step-by-step explanation:
The kind of transport utilized when no cell energy is required is called passive transport. Unlike active transport, passive transport does not require energy from the cell. Substances move across the cell membrane from an area of higher to lower concentration, a process known as diffusion, which relies on the concentration gradient to facilitate this movement.
Passive transport is the kind of transport that is utilized when no cell energy is required. Substances move from an area of higher concentration to an area of lower concentration in passive transport. This process does not require the cell to exert any energy. Diffusion is a type of passive transport where substances move down their concentration gradient.