Answer:
the type of molecule-destroying enzyme he used
Explanation:
Frederick Griffith and Oswald Avery were scientific researchers who discovered DNA. Frederick Griffith began the research and Oswald Avery continued his research in 1944 when they made the discovery of DNA. When Avery repeated Griffith's research the experimental variable in Avery's experiment was the type of molecule-destroying enzyme he used.
Answer:
B--- pay careful attention to what you are observing.
Explanation:
When you go to fast when making observations, you can mess up. When you take your time and pay careful attention when making observations, there is a chance you could mess up, but it is very slim.
Answer:
sinoatrial node and atrioventricular node
