The diagram shows an experiment to investigate photosynthesis. What is the most abundant gas present at the top of the tube at the end of the experiment?
【简答题】Cathy: Hello! This is Cathy. Is Tom there?Jack: I’m sorry.A. Would you like me to give him a message? B. Tom isn’t in right now. C. Please ask him to call me back as soon as he comes back. D. Could yo...