As you look under a microscope you see a nucleus with a large density of nucleolus. What inference can you make about that cell?

It is an eukaryotic cell.

Explanation:

In a eukaryotic cell, the nucleus is the most prominent cell organelle which can be seen through a microscope. Eukaryotic cells contain a definite or true nucleus because it is enclosed by a nuclear membrane. Within the nucleus, a dense body called nucleolus is present in the nucleoplasm. Thus, it can be inferred that the given cell is a eukaryotic cell.