Why do you think the eukaryotic dna requires multiple origins of replication?

If your on plato its Eukaryotic DNA is much larger and replication at multiple origins helps reduce the time required for whole genomes to replicate

The replication origin also known as the origin of replication is a specific sequence in a genome at which the process of replication begins. The prokaryotic chromosomes exhibit one origin of replication, while the eukaryotic chromosomes exhibit multiple origins or replication.  

This is mainly because the eukaryotic chromosomes are much bigger, therefore, multiple origins are required to replicate the whole chromosome in a short time duration. The prokaryotic chromosomes are small, thus, one origin of replication suffice.