Question

type of transport?
outside
plasma
membrane
inside
how do you know?

Explanation:

Step1: Analyze the movement direction

The substance is moving from an area of higher concentration (outside) to an area of lower concentration (inside) as indicated by the arrow.

Step2: Check for protein channels

There is no protein channel shown in the diagram.

Answer:

Simple diffusion. Because the substance moves down its concentration gradient (from high to low concentration) and there is no protein channel (which would indicate facilitated diffusion).