Electric current in a solid metal conductor is caused by the movement of what ?

Electric current in a solid metal conductor is caused by the movement of electric charge. An electric current is the flow of electric charge. An electron current, the flow of electrons, contributes to an electric current since the electron 'carries' negative electric charge. The flow of ions also contributes to an electric current in, for example, the electrolyte of an electrochemical cell. 

Texture and composition are different because they are not the same aspect. texture has to do with feel and so on, where as composition is the chemical makeup which you cant touch like you can texture.