What is 1 advantage/disadvantage of having multiple chromosomes?

Answer 1

The advantage almost assuredly is that having 1 huge long chromosome (or set of 2 huge long chromosomes) would a reduced likelihood that part of the chromosome would not reproduce properly, and thus a significant amount of genetic data lost. For example, a human has 46 chromosomes (2 sets of 23). If 1 chromosome is chopped in half, you've lost 1/92nds of your genetic data (1/2 of 1/46). If a human only had 2 chromosomes and lost half of one, it would have lost 1/4 of the genetic data - almost certainly fatal to the cell (or person, if it's an embryo)

A disadvantage would probably be that cell replication does become somewhat more complex, making errors more common (if not as drastic).