Compare and contrast single unit smooth muscle (visceral muscle) (give an example) and multi-unit smooth muscle (give an example)

A. Single unit smooth muscles, like those in the digestive tract, contract as a coordinated unit, while multi-unit smooth muscles, such as in the iris of the eye, have individual fibers that contract independently.
B. Single unit smooth muscles are under voluntary control, while multi-unit smooth muscles are controlled involuntarily.
C. Examples of single unit smooth muscles include the uterus, while examples of multi-unit smooth muscles include the airways in the lungs.
D. Single unit smooth muscles contract quickly and forcefully, while multi-unit smooth muscles contract slowly and rhythmically.