Question

sphincter, or dilator, muscles are special circular muscles that open and close to control the passage of substances.

1. true
2. false

question 10 (2.5 points)
the ability of a muscle to shorten in response to a suitable stimulus is called ______.

excitatibility
elasticity
contractility
extensibility

Explanation:

First Question (True/False about Sphincter Muscles)

Sphincter (or dilator) muscles are circular and control substance passage by opening/closing, so the statement is true.

• Excitability: Muscle's response to stimulus (not shortening).
• Elasticity: Ability to recoil after stretching.
• Contractility: Ability to shorten with stimulus (matches definition).
• Extensibility: Ability to stretch.

So the correct term is contractility.

Answer:

1. True

Second Question (Muscle Ability)