Please choose the correct answer to the 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?

Answer1: the endocrine and skeletal systems Answer2: the circulatory and respiratory systems Answer3: the skeletal and muscular systems Answer4: the integumentary and excretory system

Answer format: answer1/answer2/answer3/answer4