Which taxonomic classification below contains the fewest organisms

What is the answer for the complicated molecules that make up living things usually contain carbon. why is carbon so important in these molecules?

What characteristic make legumes a good food source for food insecure populations

This question is only for applicants to scholars for medicine or scholars for dental medicine: what aspects about medicine (or dental medicine) intrigue you? describe how these aspects influence your life. (100-650 words)