Which one of the following is the correct pairing of a body part and the kind of muscle tissue which moves it?
The correct option is B. Iris - Involuntary smooth muscle.
Involuntary smooth muscles make up the iris as it controls the size of the pupil. This is important for accommodation of the eyes in presence of different light intensities.
The structure of the heart is made up of cardiac muscles, which are involuntary muscles that help with pumping of blood. Biceps of the upper arm are made up of striated muscles as the muscle contraction can be controlled by the individual. Abdominal wall is made up of smooth muscle fibers that help with the peristaltic movement which occurs in an involuntary manner.