Final answer:
The relationship between genome size and organismal complexity is that more complex organisms generally have larger genomes, but there are exceptions.
Step-by-step explanation:
The relationship between genome size and organismal complexity is that more complex organisms generally have larger genomes, but there are many notable exceptions. Genome size refers to the amount of DNA in one copy of a species' chromosomes. While there is a tendency for more complex organisms to have larger genomes, it is not a strict rule and there are organisms with relatively small genomes that are still highly complex.