the endocrine and skeletal systems the circulatory and respiratory systems the skeletal and muscular systems the integumentary and excretory system
I gave my students this multiple choice question: In eukaryotic organisms, microtubules give cells structure, and microfilaments help the cell contract and move. Together, they combine to perform functions similar to what two human body systems?

Only one answer is correct among these 4 choices:
- the endocrine and skeletal systems
- the circulatory and respiratory systems
- the skeletal and muscular systems
- the integumentary and excretory system

Could you tell me which one is correct?

the skeletal and muscular systems