Question

which of the following is true?
smooth muscle lacks the thin and thick filaments characteristic of skeletal muscle.
skeletal muscle fibers tend to be shorter than smooth muscle fibers.
skeletal muscle fibers contain sarcomeres; smooth muscle fibers do not.
skeletal muscle lacks the coarse connective tissue sheaths that are found in smooth muscle.

Explanation:

• Smooth muscle has thin and thick filaments, so the first option is wrong.
• Skeletal muscle fibers are longer than smooth muscle fibers, so the second option is wrong.
• Skeletal muscle has sarcomeres (the basic contractile units), and smooth muscle does not, so the third option is correct.
• Skeletal muscle has connective tissue sheaths (like epimysium, perimysium, endomysium), while smooth muscle has different connective tissue arrangements but not what the fourth option states.

Answer:

Skeletal muscle fibers contain sarcomeres; smooth muscle fibers do not.