Which of the following processes does not occur against the concentration gradient?

As cells in the cortex are loosely packed,what is the effect on water movement?

In a $X$, both molecules cross the membrane in the same direction; in an $Y$, they move in opposite directions.

Select the incorrect statement with respect to facilitated diffusion.

This transport occurs along the concentration gradient.

Read the following statements regarding porins and select the correct option given below:
$I$. Porins are transport proteins.
$II$. Channel proteins are a type of transport protein,which are usually gated.
$III$. Carrier protein binds the particular solute to be transported.
$IV$. Particular solute is delivered to the other side of the membrane by carrier proteins.