I just took a test in school today. What question was I asked?

Question I was asked: Which two body systems are involved in inhaling oxygen and exhaling carbon dioxide?

I just took a test in school today. What question was I asked?

Question I was asked: Which of these is a safe practice in a laboratory investigation when working with chemicals?

I just took a test in school today. What question was I asked?

Question I was asked:
Which of these cell structures converts nutrients to energy for cell functions?