The Upper Esophageal Sphincter Is Composed of a Circular Band

question 67

Multiple Choice

The upper esophageal sphincter is composed of a circular band of skeletal muscle. The lower esophageal sphincter is composed of a circular band of smooth muscle.

• A) Both statements are true.
• B) Both statements are false.
• C) The first statement is true; the second is false.
• D) The second statement is true; the first is false.

---

Definitions:

Blood Type A

A blood group in the ABO blood typing system, characterized by the presence of the A antigen on the surface of red blood cells.

Joint Frequency Distribution

a table showing the frequency of two or more variables occurring together in a set of observations.

Female

Referring to the sex of an organism, or part of an organism, which is characteristic of producing non-mobile ova (egg cells) and typically possessing XX chromosomes in mammals.

At Most

A term used to indicate a maximum limit or boundary in mathematical expressions or everyday language.