Final answer:
There are more prokaryotic cells on Earth compared to the estimated number of stars in the known universe.
Step-by-step explanation:
The global number of prokaryotes on Earth has been estimated to be 4-6 x 1030 cells, which is many million times more than the number of stars in the visible universe. Prokaryotes are single-celled organisms that lack a nucleus and other membrane-bound organelles. They are found in various environments, including soil, water, and inside other organisms. Therefore, there are more prokaryotic cells on Earth compared to the estimated number of stars in the known universe.