Telomere Restoration Enables Biological Immortality

Steps:

• Recognize that T. dohrnii's immortality stems from its ability to revert to a juvenile stage, cycling life without aging.
• Note that biological age is indeterminable because cells lack typical aging markers like telomere erosion.
• Recall that telomeres shorten with each cell division, eventually causing senescence and limiting lifespan in most organisms.
• Identify that restoring telomeres allows indefinite divisions, preventing aging and matching the observations.

Why C is correct:

• Telomeres cap chromosome ends and shorten progressively; telomerase restores their length, enabling unlimited replication without cellular aging, as defined in the Hayflick limit.

Why the others are wrong:

• A: A long G phase delays cell progression but does not halt telomere shortening or aging.
• B: A short S phase accelerates DNA synthesis but fails to address telomere attrition.
• D: Fewer chromosomes reduce complexity but do not prevent age-related degradation or enable rejuvenation.

Final answer: C