The bones
The question itself needs to be more fundementally defined in its context as the human body contains many "solids". These include but are not limited to; blood (clots), bones, eyeballs, mucus (solidified), skin and of course not forgetting waste and other stuff.
matter flow
First the human body is wholly composed of matter. The body takes in matter to be broken down through digestion, to replenish and fuel the body. This matter is converted into new molecules constantly. The body also excretes gaseous, liquid and solid matter through respiration, metabolism, and excretion of waste.
Solid
The part of the body where you would find grey matter is in the brain. Grey matter is responsible for muscle control and sensory perception such as sight, hearing and speech.
A pencil is in the solid state of matter.
Feces Body's solid waste: the body's solid waste matter, composed of undigested food, bacteria, water, and bile pigments and discharged from the bowel through the anus.
Yes, more or less. Except for any grease, it is a collection of solid matter. It is not a liquid nor a gas. The body is made out of wood, fiberglass, or some sort of composite material. The frames for the wheels are made out of aluminum or some alloy (metal). Then the wheels are made out of some sort of rubber or plastic. Then there are bearings, screws, and nuts, and those are made out of steel or other metal. So for the most part, a skateboard is made from solid matter.
It is known as the anus or rectum.
The human body contains most commonly the solid and liquid states of matter. Solids can include bones and teeth, while liquids can include blood and other bodily fluids. There are also gases present in the body, such as oxygen and carbon dioxide within the respiratory system.
The solid matter would get wet!