Final answer:
Telomeres prevent incomplete replication of linear chromosomes in eukaryotes by providing a buffer against DNA loss during replication, with the enzyme telomerase elongating the telomeres to facilitate complete DNA replication.
Step-by-step explanation:
How do the linear chromosomes in eukaryotes ensure that its ends are replicated completely? The correct answer is b) Telomeres prevent incomplete replication. Telomeres are repetitive nucleotide sequences at the ends of eukaryotic chromosomes that protect the chromosome from deterioration or fusion with neighboring chromosomes. During replication, these telomeres are shortened because the lagging strand requires a primer to start replication, and there is no way to place a primer at the very end of the chromosome.
This is where telomerase comes into play; this enzyme elongates the telomeres, providing a buffer zone against the loss of more vital DNA sequences. Telomerase attaches to the end of the chromosome and extends the telomeres, allowing the DNA polymerase to complete replication of the lagging strand without loss of important genomic information.