A correct balance of oxygen and carbon dioxide must be maintained in the human body to survive. Which system is responsible taking in oxygen and releasing carbon dioxide to the external environment to maintain this internal balance? A. the respiratory system
B. the circulatory system
C. the digestive system
D. the nervous system

According to the article,"social credit" is question 3 options: an experiment to people talk on-line a farming experiment that hurt people under mao ze dong using someone else's data from the internet, to give or take away things such as the right to buy an airline ticket a credit you get in china for having friends in real life, and not just on social media