are microscopic do not contain DNA reproduce very quickly cause infectious diseases
I gave my students this multiple choice question: Although change in multicellular species usually takes thousands of years, some species of bacteria undergo major changes in just a few years. One reason for this difference is that these bacteria

Only one answer is correct among these 4 choices:
- are microscopic
- do not contain DNA
- reproduce very quickly
- cause infectious diseases

Could you tell me which one is correct?

reproduce very quickly