Question

replication bubbles
when all of the bubbles have collided, two new strands of dna have been made. having multiple
replication bubbles, and therefore multiple sites of replication, increases the speed that dna is
copied. instead of taking a month to replicate dna, it takes only a couple of hours
origin of
replication
replication
forks
replication
bubble
2 replicated
strands of dna

1. multiple sites of replication allow cells to duplicate their dna

Explanation:

The text and diagram explain that multiple replication bubbles (multiple sites of replication) increase the speed of DNA replication. Instead of taking a month, it takes a couple of hours. So the blank should be filled with a word related to speed, like "faster" or "more quickly". From the context, the key point is that multiple replication sites make DNA duplication faster.

Answer:

faster (or more quickly)