Which term describes the ability to move by shortening?

Which term describes the ability to move by shortening?

• A. Movement
• B. Growth
• C. Digestion
• D. Excretion

Answer: (A)

Movement refers to the ability to change position or location, and in humans it happens when muscles contract and shorten, pulling on bones to produce motion. This shortening of muscle fibers is the mechanism behind moving limbs and body parts, so movement is the term that best describes moving by shortening. The other processes—growth (getting bigger), digestion (breakdown of food), and excretion (removal of wastes)—do not entail shortening to create motion.

Movement refers to the ability to change position or location, and in humans it happens when muscles contract and shorten, pulling on bones to produce motion. This shortening of muscle fibers is the mechanism behind moving limbs and body parts, so movement is the term that best describes moving by shortening. The other processes—growth (getting bigger), digestion (breakdown of food), and excretion (removal of wastes)—do not entail shortening to create motion.