Q: What portion of the human body consists of human cells?
A: About the amount from the knee of one leg down to the foot. The rest is bacteria.
This reminds me of commercial television. We commonly regard TV as a medium of art and communication financed by advertising. Actually, however, it is an advertising medium to which viewers are lured by the programming. Ironically, a small portion of this programming is sometimes thought to have real value and significance.
Similarly, we commonly regard human life as The Most Important Thing in the Universe, while bacteria are incidental fellow-travelers, sometimes useful, sometimes troublesome. Actually, however, bacteria dominate life on Earth, and human beings are merely hosts that provide food and shelter for bacteria. Ironically, some of these bacterial hosts occasionally write War and Peace or paint Guernica.