In the Middle Ages, most scientists believed that the world was made from four simple elements and that almost everything was a mixture. What type of pure substance had they not yet discovered?

i just learnt this recently but i need to look through my notes again

smooth muscle is composed of involuntary muscles found within the walls of organs and structures such as the esophagus, stomach, intestines, and blood vessels. those muscles push materials like food or blood through organs. unlike skeletal muscle, smooth muscle can never be under your control.

your answer would be “dry”