Please choose the correct answer to the question: Which statement correctly describes a relationship between two human body systems?

Answer1: The digestive system absorbs nutrients which are transported by the nervous system. Answer2: The digestive system absorbs nutrients which are transported by the circulatory system. Answer3: The circulatory system exchanges gases which are transported by the nervous system. Answer4: The circulatory system exchanges gases which are transported by the digestive system.

Answer format: answer1/answer2/answer3/answer4