Hybrid orbitals of the sp3d type occur in sets of four. true or false?

well , it's true because they are of sp3d type occur on sets of four

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.

they are all solids.