Question

question 8: what is one function of the circulatory system demonstrated in this experiment? (1 point) breaking down food for energy delivering oxygen and nutrients to tissues controlling movement with muscles producing hormones question 9: why does breathing - rate increase during exercise? (1 point) to remove carbon dioxide and bring in more oxygen to lower body temperature to help digest food faster to keep the heart from overworking

Explanation:

For Question 8, the circulatory system's main function is to transport oxygen and nutrients to tissues and remove waste. Breaking down food is for digestion, muscle - control is related to the muscular and nervous systems, and hormone - production is mainly by the endocrine system.
For Question 9, during exercise, the body's cells need more oxygen and need to remove more carbon dioxide. So, the breathing - rate increases to meet this demand. Lowering body temperature is mainly through sweating, digestion is not directly related to increased breathing during exercise, and keeping the heart from overworking is not the main reason for increased breathing.

Answer:

Question 8: Delivering oxygen and nutrients to tissues
Question 9: To remove carbon dioxide and bring in more oxygen