Most mammals have roughly the same amount of total genomic DNA. What would you predict about the size of mammalian chromosomes in an organism with a low chromosome number? What about mammals with a high chromosome number. Give some examples of organisms.

It's not the amount of DNA that determines the size of chromosomes in a specie but the amount of genetic information that is needed  to be stored may be loosely (more euchromatin) and densly tight (more heterochromatin). For example, Potato and Chimpanzee share sma enumber of 48 chromosomes but as a mammal with complex organization, a chimpanzee's chromosomes are highly densely packed as compared to that of potato that stores only potato level information.