Which of the following best describes the chromosomes of eukaryotic cells?
1. more-complex eukaryotes have more chromosomes than simpler ones do.
2. different kinds of eukaryotes have different numbers of chromosomes.
3. the chromosomes in a pair contain very different genetic information.
4. each of the chromosomes contains one copy of circular dna.

2. Different kinds of eukaryotes have different numbers of chromosomes.

There are differences between Eukaryotic and Prokaryotic cells. This difference is considered to be the most important distinction between groups of organisms. A Prokaryotic cell does not contain a nucleus. It only contains one chromosome and is a single-celled organism. It was the only form of life on earth for millions of years. Examples of a Prokaryotic cell are the different types of bacteria present today. 
A Eukaryotic cell contains a nucleus; more than one chromosome and is typically a multi-celled organism.  Both plant and animal cells are eukaryotic cells.