I need an explanation as to why you are correct!

How does the substance in a mudflow form?

Rain mixes with soil.

Large rocks mix with water.

Soil and paper debris are combined.

Loosely connected rocks bind together.

A. Mudflow is a type of liquefaction. Basically what happens is water acts as a lubricant and when a force such as gravity is present and the water is saturated enough it will begin to act more like a fluid than a solid. The additional weight from the water is also a big factor. As an experiment, Get a pile of dirt and put it on a steep ramp. Then get a mister bottle and start spraying the dirt. eventually, the added weight of the water plus the decreased friction between particles will cause the dirt to move down the ramp. This is the same process as a mudflow.

Note: grain sizes below silt aren't as likely to do this as they become more cohesive when hydrated.