Question

the muscularis usually contains two layers of ________ muscle.
multiple choice
smooth
striated
skeletal

Explanation:

The muscularis externa (muscularis) of the digestive tract (except upper esophagus and anal canal) typically has two layers of smooth muscle. Smooth muscle in the muscularis is involuntary. Striated muscle (skeletal muscle) is only in specific regions like the upper esophagus. So the correct muscle type for the general muscularis (as per most of the digestive tract's muscularis) is smooth.

Answer:

smooth