Question: Which statement is correct about the flatworm’s muscular system?

Answer: it consists of two layers of muscle

Question: Which statement is correct about the human muscular system?

Answer: smooth and cardiac muscles operate involuntarily

Question: When a person bends an arm, a different muscle is being used to bring it back to the original position.

Why can’t the same muscle be used to both bend and unbend the arm?

Answer: muscles can only pull, not push