In a solid state, the particles of a substance are placed tightly and are fixed in certain places, they cannot move relative to each other, but only vibrate around the point of attachment, therefore solids almost do not compress, cannot flow and retain the shape provided to them.
In the liquid state, the molecules are also densely located, but they are free and can move relative to each other, therefore, liquid substances also hardly compress, but can flow and take the form of a vessel in which they are stored.
In a gaseous state, the molecules of a substance are at great distances from each other and move freely. As a result, gaseous substances are easily compressed and expanded and occupy the entire volume of the vessel in which they are stored, acquiring its forms.
Gases do not have their own shape and volume, liquids have their own volume, but they have no shape, and solids retain their shape and volume.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.