Why paper sticks together when wet

The paper fibres of wet toilet paper absorb water molecules, which cling to each other like weak glue. The water molecules are held together by cohesive forces, as they are polar and produce hydrogen bindings to their closest neighbours

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.