Answer:
Streptococcus mutans.
Explanation:
Streptococcus mutans is the bacteria (it is still a microorganism) that predominatly causes tooth decay. It is present in all areas of the mouth.
Answer:
oxygen: it was the result of biological activities. There were such stable continental shelf environments, which were rare in the Archean, developed after 2.5 billion years ago, facilitating the growth of photosynthetic organisms and thus oxygen production.
I believe your answer should be glacial drift