Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: 
As cells divide, their chromosomes get shorter. This is because the telomeres, the DNA sequences at both ends of a chromosome, lose material every time the DNA is replicated. The older the animal is, the shorter its telomeres will be, because of the number of cell cycles the cells have been through This is a natural part of aging. So, what happens to the clone if its transferred nucleus is already fairly old? Will the shortened telomeres affect its development or lifespan? The answer is still unclear. But starting a new organisms with "old" DNA with shortened telomeres is bound to have some effects, at least in some clones. Some cloned animals may be affected, others may not. Dolly the sheep's chromosomes did have shorter telomere lengths than normal. This means that Dolly's cells were aging faster than the cells from a normal sheep.


Question: What happens to an animal's telomeres as it ages?
shorten
Telomeres get shorter.