Identify the following process and choose the correct option.

Identify the water transport pathways $P$ and $Q$ shown in the given figure.

The diffusion of any substance across a membrane depends on which of the following?

What are the factors affecting the rate of diffusion?

Read carefully the following statements and choose the right answer from the options given below.
$I$. Diffusion is a slow process and it does not depend upon the living system.
$II$. Usually,the process of diffusion does not need energy.
$III$. Diffusion can occur from one part of a cell to another part of the same cell,or from one cell to another,and from one tissue to another tissue.
$IV$. Diffusion is a rapid process over short distances,but extremely slow over long distances.

Facilitated diffusion is characterized by all,except